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Diffstat (limited to 'gfx/wr/swgl/src/composite.h')
| -rw-r--r-- | gfx/wr/swgl/src/composite.h | 1386 |
1 files changed, 1386 insertions, 0 deletions
diff --git a/gfx/wr/swgl/src/composite.h b/gfx/wr/swgl/src/composite.h new file mode 100644 index 0000000000..70acabeca4 --- /dev/null +++ b/gfx/wr/swgl/src/composite.h @@ -0,0 +1,1386 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +// Converts a pixel from a source format to a destination format. By default, +// just return the value unchanged as for a simple copy. +template <typename P, typename U> +static ALWAYS_INLINE P convert_pixel(U src) { + return src; +} + +// R8 format maps to BGRA value 0,0,R,1. The byte order is endian independent, +// but the shifts unfortunately depend on endianness. +template <> +ALWAYS_INLINE uint32_t convert_pixel<uint32_t>(uint8_t src) { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return (uint32_t(src) << 16) | 0xFF000000; +#else + return (uint32_t(src) << 8) | 0x000000FF; +#endif +} + +// RG8 format maps to BGRA value 0,G,R,1. +template <> +ALWAYS_INLINE uint32_t convert_pixel<uint32_t>(uint16_t src) { + uint32_t rg = src; +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return ((rg & 0x00FF) << 16) | (rg & 0xFF00) | 0xFF000000; +#else + return (rg & 0xFF00) | ((rg & 0x00FF) << 16) | 0x000000FF; +#endif +} + +// RGBA8 format maps to R. +template <> +ALWAYS_INLINE uint8_t convert_pixel<uint8_t>(uint32_t src) { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return (src >> 16) & 0xFF; +#else + return (src >> 8) & 0xFF; +#endif +} + +// RGBA8 formats maps to R,G. +template <> +ALWAYS_INLINE uint16_t convert_pixel<uint16_t>(uint32_t src) { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return ((src >> 16) & 0x00FF) | (src & 0xFF00); +#else + return (src & 0xFF00) | ((src >> 16) & 0x00FF); +#endif +} + +// R8 format maps to R,0. +template <> +ALWAYS_INLINE uint16_t convert_pixel<uint16_t>(uint8_t src) { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return src; +#else + return uint16_t(src) << 8; +#endif +} + +// RG8 format maps to R. +template <> +ALWAYS_INLINE uint8_t convert_pixel<uint8_t>(uint16_t src) { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return src & 0xFF; +#else + return src >> 8; +#endif +} + +template <bool COMPOSITE, typename P> +static inline void copy_row(P* dst, const P* src, int span) { + // No scaling, so just do a fast copy. + memcpy(dst, src, span * sizeof(P)); +} + +template <> +void copy_row<true, uint32_t>(uint32_t* dst, const uint32_t* src, int span) { + // No scaling, so just do a fast composite. + auto* end = dst + span; + while (dst + 4 <= end) { + WideRGBA8 srcpx = unpack(unaligned_load<PackedRGBA8>(src)); + WideRGBA8 dstpx = unpack(unaligned_load<PackedRGBA8>(dst)); + PackedRGBA8 r = pack(srcpx + dstpx - muldiv255(dstpx, alphas(srcpx))); + unaligned_store(dst, r); + src += 4; + dst += 4; + } + if (dst < end) { + WideRGBA8 srcpx = unpack(partial_load_span<PackedRGBA8>(src, end - dst)); + WideRGBA8 dstpx = unpack(partial_load_span<PackedRGBA8>(dst, end - dst)); + auto r = pack(srcpx + dstpx - muldiv255(dstpx, alphas(srcpx))); + partial_store_span(dst, r, end - dst); + } +} + +template <bool COMPOSITE, typename P, typename U> +static inline void scale_row(P* dst, int dstWidth, const U* src, int srcWidth, + int span, int frac) { + // Do scaling with different source and dest widths. + for (P* end = dst + span; dst < end; dst++) { + *dst = convert_pixel<P>(*src); + // Step source according to width ratio. + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + } +} + +template <> +void scale_row<true, uint32_t, uint32_t>(uint32_t* dst, int dstWidth, + const uint32_t* src, int srcWidth, + int span, int frac) { + // Do scaling with different source and dest widths. + // Gather source pixels four at a time for better packing. + auto* end = dst + span; + for (; dst + 4 <= end; dst += 4) { + U32 srcn; + srcn.x = *src; + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + srcn.y = *src; + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + srcn.z = *src; + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + srcn.w = *src; + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + WideRGBA8 srcpx = unpack(bit_cast<PackedRGBA8>(srcn)); + WideRGBA8 dstpx = unpack(unaligned_load<PackedRGBA8>(dst)); + PackedRGBA8 r = pack(srcpx + dstpx - muldiv255(dstpx, alphas(srcpx))); + unaligned_store(dst, r); + } + if (dst < end) { + // Process any remaining pixels. Try to gather as many pixels as possible + // into a single source chunk for compositing. + U32 srcn = {*src, 0, 0, 0}; + if (end - dst > 1) { + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + srcn.y = *src; + if (end - dst > 2) { + for (frac += srcWidth; frac >= dstWidth; frac -= dstWidth) { + src++; + } + srcn.z = *src; + } + } + WideRGBA8 srcpx = unpack(bit_cast<PackedRGBA8>(srcn)); + WideRGBA8 dstpx = unpack(partial_load_span<PackedRGBA8>(dst, end - dst)); + auto r = pack(srcpx + dstpx - muldiv255(dstpx, alphas(srcpx))); + partial_store_span(dst, r, end - dst); + } +} + +template <bool COMPOSITE = false> +static NO_INLINE void scale_blit(Texture& srctex, const IntRect& srcReq, + Texture& dsttex, const IntRect& dstReq, + bool invertY, const IntRect& clipRect) { + assert(!COMPOSITE || (srctex.internal_format == GL_RGBA8 && + dsttex.internal_format == GL_RGBA8)); + // Cache scaling ratios + int srcWidth = srcReq.width(); + int srcHeight = srcReq.height(); + int dstWidth = dstReq.width(); + int dstHeight = dstReq.height(); + // Compute valid dest bounds + IntRect dstBounds = dsttex.sample_bounds(dstReq).intersect(clipRect); + // Compute valid source bounds + IntRect srcBounds = srctex.sample_bounds(srcReq, invertY); + // If srcReq is outside the source texture, we need to clip the sampling + // bounds so that we never sample outside valid source bounds. Get texture + // bounds relative to srcReq and scale to dest-space rounding inward, using + // this rect to limit the dest bounds further. + IntRect srcClip = srctex.bounds() - srcReq.origin(); + if (invertY) { + srcClip.invert_y(srcReq.height()); + } + srcClip.scale(srcWidth, srcHeight, dstWidth, dstHeight, true); + dstBounds.intersect(srcClip); + // Check if clipped sampling bounds are empty + if (dstBounds.is_empty()) { + return; + } + + // Calculate source and dest pointers from clamped offsets + int srcStride = srctex.stride(); + int destStride = dsttex.stride(); + char* dest = dsttex.sample_ptr(dstReq, dstBounds); + // Clip the source bounds by the destination offset. + int fracX = srcWidth * dstBounds.x0; + int fracY = srcHeight * dstBounds.y0; + srcBounds.x0 = max(fracX / dstWidth, srcBounds.x0); + srcBounds.y0 = max(fracY / dstHeight, srcBounds.y0); + fracX %= dstWidth; + fracY %= dstHeight; + char* src = srctex.sample_ptr(srcReq, srcBounds, invertY); + // Inverted Y must step downward along source rows + if (invertY) { + srcStride = -srcStride; + } + int span = dstBounds.width(); + for (int rows = dstBounds.height(); rows > 0; rows--) { + switch (srctex.bpp()) { + case 1: + switch (dsttex.bpp()) { + case 2: + scale_row<COMPOSITE>((uint16_t*)dest, dstWidth, (uint8_t*)src, + srcWidth, span, fracX); + break; + case 4: + scale_row<COMPOSITE>((uint32_t*)dest, dstWidth, (uint8_t*)src, + srcWidth, span, fracX); + break; + default: + if (srcWidth == dstWidth) + copy_row<COMPOSITE>((uint8_t*)dest, (uint8_t*)src, span); + else + scale_row<COMPOSITE>((uint8_t*)dest, dstWidth, (uint8_t*)src, + srcWidth, span, fracX); + break; + } + break; + case 2: + switch (dsttex.bpp()) { + case 1: + scale_row<COMPOSITE>((uint8_t*)dest, dstWidth, (uint16_t*)src, + srcWidth, span, fracX); + break; + case 4: + scale_row<COMPOSITE>((uint32_t*)dest, dstWidth, (uint16_t*)src, + srcWidth, span, fracX); + break; + default: + if (srcWidth == dstWidth) + copy_row<COMPOSITE>((uint16_t*)dest, (uint16_t*)src, span); + else + scale_row<COMPOSITE>((uint16_t*)dest, dstWidth, (uint16_t*)src, + srcWidth, span, fracX); + break; + } + break; + case 4: + switch (dsttex.bpp()) { + case 1: + scale_row<COMPOSITE>((uint8_t*)dest, dstWidth, (uint32_t*)src, + srcWidth, span, fracX); + break; + case 2: + scale_row<COMPOSITE>((uint16_t*)dest, dstWidth, (uint32_t*)src, + srcWidth, span, fracX); + break; + default: + if (srcWidth == dstWidth) + copy_row<COMPOSITE>((uint32_t*)dest, (uint32_t*)src, span); + else + scale_row<COMPOSITE>((uint32_t*)dest, dstWidth, (uint32_t*)src, + srcWidth, span, fracX); + break; + } + break; + default: + assert(false); + break; + } + dest += destStride; + // Step source according to height ratio. + for (fracY += srcHeight; fracY >= dstHeight; fracY -= dstHeight) { + src += srcStride; + } + } +} + +template <bool COMPOSITE> +static void linear_row_blit(uint32_t* dest, int span, const vec2_scalar& srcUV, + float srcDU, sampler2D sampler) { + vec2 uv = init_interp(srcUV, vec2_scalar(srcDU, 0.0f)); + for (; span >= 4; span -= 4) { + auto srcpx = textureLinearPackedRGBA8(sampler, ivec2(uv)); + unaligned_store(dest, srcpx); + dest += 4; + uv.x += 4 * srcDU; + } + if (span > 0) { + auto srcpx = textureLinearPackedRGBA8(sampler, ivec2(uv)); + partial_store_span(dest, srcpx, span); + } +} + +template <> +void linear_row_blit<true>(uint32_t* dest, int span, const vec2_scalar& srcUV, + float srcDU, sampler2D sampler) { + vec2 uv = init_interp(srcUV, vec2_scalar(srcDU, 0.0f)); + for (; span >= 4; span -= 4) { + WideRGBA8 srcpx = textureLinearUnpackedRGBA8(sampler, ivec2(uv)); + WideRGBA8 dstpx = unpack(unaligned_load<PackedRGBA8>(dest)); + PackedRGBA8 r = pack(srcpx + dstpx - muldiv255(dstpx, alphas(srcpx))); + unaligned_store(dest, r); + + dest += 4; + uv.x += 4 * srcDU; + } + if (span > 0) { + WideRGBA8 srcpx = textureLinearUnpackedRGBA8(sampler, ivec2(uv)); + WideRGBA8 dstpx = unpack(partial_load_span<PackedRGBA8>(dest, span)); + PackedRGBA8 r = pack(srcpx + dstpx - muldiv255(dstpx, alphas(srcpx))); + partial_store_span(dest, r, span); + } +} + +template <bool COMPOSITE> +static void linear_row_blit(uint8_t* dest, int span, const vec2_scalar& srcUV, + float srcDU, sampler2D sampler) { + vec2 uv = init_interp(srcUV, vec2_scalar(srcDU, 0.0f)); + for (; span >= 4; span -= 4) { + auto srcpx = textureLinearPackedR8(sampler, ivec2(uv)); + unaligned_store(dest, srcpx); + dest += 4; + uv.x += 4 * srcDU; + } + if (span > 0) { + auto srcpx = textureLinearPackedR8(sampler, ivec2(uv)); + partial_store_span(dest, srcpx, span); + } +} + +template <bool COMPOSITE> +static void linear_row_blit(uint16_t* dest, int span, const vec2_scalar& srcUV, + float srcDU, sampler2D sampler) { + vec2 uv = init_interp(srcUV, vec2_scalar(srcDU, 0.0f)); + for (; span >= 4; span -= 4) { + auto srcpx = textureLinearPackedRG8(sampler, ivec2(uv)); + unaligned_store(dest, srcpx); + dest += 4; + uv.x += 4 * srcDU; + } + if (span > 0) { + auto srcpx = textureLinearPackedRG8(sampler, ivec2(uv)); + partial_store_span(dest, srcpx, span); + } +} + +template <bool COMPOSITE = false> +static NO_INLINE void linear_blit(Texture& srctex, const IntRect& srcReq, + Texture& dsttex, const IntRect& dstReq, + bool invertX, bool invertY, + const IntRect& clipRect) { + assert(srctex.internal_format == GL_RGBA8 || + srctex.internal_format == GL_R8 || srctex.internal_format == GL_RG8); + assert(!COMPOSITE || (srctex.internal_format == GL_RGBA8 && + dsttex.internal_format == GL_RGBA8)); + // Compute valid dest bounds + IntRect dstBounds = dsttex.sample_bounds(dstReq); + dstBounds.intersect(clipRect); + // Check if sampling bounds are empty + if (dstBounds.is_empty()) { + return; + } + // Initialize sampler for source texture + sampler2D_impl sampler; + init_sampler(&sampler, srctex); + sampler.filter = TextureFilter::LINEAR; + // Compute source UVs + vec2_scalar srcUV(srcReq.x0, srcReq.y0); + vec2_scalar srcDUV(float(srcReq.width()) / dstReq.width(), + float(srcReq.height()) / dstReq.height()); + if (invertX) { + // Advance to the end of the row and flip the step. + srcUV.x += srcReq.width(); + srcDUV.x = -srcDUV.x; + } + // Inverted Y must step downward along source rows + if (invertY) { + srcUV.y += srcReq.height(); + srcDUV.y = -srcDUV.y; + } + // Skip to clamped source start + srcUV += srcDUV * (vec2_scalar(dstBounds.x0, dstBounds.y0) + 0.5f); + // Scale UVs by lerp precision + srcUV = linearQuantize(srcUV, 128); + srcDUV *= 128.0f; + // Calculate dest pointer from clamped offsets + int bpp = dsttex.bpp(); + int destStride = dsttex.stride(); + char* dest = dsttex.sample_ptr(dstReq, dstBounds); + int span = dstBounds.width(); + for (int rows = dstBounds.height(); rows > 0; rows--) { + switch (bpp) { + case 1: + linear_row_blit<COMPOSITE>((uint8_t*)dest, span, srcUV, srcDUV.x, + &sampler); + break; + case 2: + linear_row_blit<COMPOSITE>((uint16_t*)dest, span, srcUV, srcDUV.x, + &sampler); + break; + case 4: + linear_row_blit<COMPOSITE>((uint32_t*)dest, span, srcUV, srcDUV.x, + &sampler); + break; + default: + assert(false); + break; + } + dest += destStride; + srcUV.y += srcDUV.y; + } +} + +// Whether the blit format is renderable. +static inline bool is_renderable_format(GLenum format) { + switch (format) { + case GL_R8: + case GL_RG8: + case GL_RGBA8: + return true; + default: + return false; + } +} + +extern "C" { + +void BlitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, + GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, + GLbitfield mask, GLenum filter) { + assert(mask == GL_COLOR_BUFFER_BIT); + Framebuffer* srcfb = get_framebuffer(GL_READ_FRAMEBUFFER); + if (!srcfb) return; + Framebuffer* dstfb = get_framebuffer(GL_DRAW_FRAMEBUFFER); + if (!dstfb) return; + Texture& srctex = ctx->textures[srcfb->color_attachment]; + if (!srctex.buf) return; + Texture& dsttex = ctx->textures[dstfb->color_attachment]; + if (!dsttex.buf) return; + assert(!dsttex.locked); + if (srctex.internal_format != dsttex.internal_format && + (!is_renderable_format(srctex.internal_format) || + !is_renderable_format(dsttex.internal_format))) { + // If the internal formats don't match, then we may have to convert. Require + // that the format is a simple renderable format to limit combinatoric + // explosion for now. + assert(false); + return; + } + // Force flipped Y onto dest coordinates + if (srcY1 < srcY0) { + swap(srcY0, srcY1); + swap(dstY0, dstY1); + } + bool invertY = dstY1 < dstY0; + if (invertY) { + swap(dstY0, dstY1); + } + IntRect srcReq = IntRect{srcX0, srcY0, srcX1, srcY1} - srctex.offset; + IntRect dstReq = IntRect{dstX0, dstY0, dstX1, dstY1} - dsttex.offset; + if (srcReq.is_empty() || dstReq.is_empty()) { + return; + } + IntRect clipRect = {0, 0, dstReq.width(), dstReq.height()}; + prepare_texture(srctex); + prepare_texture(dsttex, &dstReq); + if (!srcReq.same_size(dstReq) && srctex.width >= 2 && filter == GL_LINEAR && + srctex.internal_format == dsttex.internal_format && + is_renderable_format(srctex.internal_format)) { + linear_blit(srctex, srcReq, dsttex, dstReq, false, invertY, dstReq); + } else { + scale_blit(srctex, srcReq, dsttex, dstReq, invertY, clipRect); + } +} + +typedef Texture LockedTexture; + +// Lock the given texture to prevent modification. +LockedTexture* LockTexture(GLuint texId) { + Texture& tex = ctx->textures[texId]; + if (!tex.buf) { + assert(tex.buf != nullptr); + return nullptr; + } + if (__sync_fetch_and_add(&tex.locked, 1) == 0) { + // If this is the first time locking the texture, flush any delayed clears. + prepare_texture(tex); + } + return (LockedTexture*)&tex; +} + +// Lock the given framebuffer's color attachment to prevent modification. +LockedTexture* LockFramebuffer(GLuint fboId) { + Framebuffer& fb = ctx->framebuffers[fboId]; + // Only allow locking a framebuffer if it has a valid color attachment. + if (!fb.color_attachment) { + assert(fb.color_attachment != 0); + return nullptr; + } + return LockTexture(fb.color_attachment); +} + +// Reference an already locked resource +void LockResource(LockedTexture* resource) { + if (!resource) { + return; + } + __sync_fetch_and_add(&resource->locked, 1); +} + +// Remove a lock on a texture that has been previously locked +void UnlockResource(LockedTexture* resource) { + if (!resource) { + return; + } + if (__sync_fetch_and_add(&resource->locked, -1) <= 0) { + // The lock should always be non-zero before unlocking. + assert(0); + } +} + +// Get the underlying buffer for a locked resource +void* GetResourceBuffer(LockedTexture* resource, int32_t* width, + int32_t* height, int32_t* stride) { + *width = resource->width; + *height = resource->height; + *stride = resource->stride(); + return resource->buf; +} + +// Extension for optimized compositing of textures or framebuffers that may be +// safely used across threads. The source and destination must be locked to +// ensure that they can be safely accessed while the SWGL context might be used +// by another thread. Band extents along the Y axis may be used to clip the +// destination rectangle without effecting the integer scaling ratios. +void Composite(LockedTexture* lockedDst, LockedTexture* lockedSrc, GLint srcX, + GLint srcY, GLsizei srcWidth, GLsizei srcHeight, GLint dstX, + GLint dstY, GLsizei dstWidth, GLsizei dstHeight, + GLboolean opaque, GLboolean flipX, GLboolean flipY, + GLenum filter, GLint clipX, GLint clipY, GLsizei clipWidth, + GLsizei clipHeight) { + if (!lockedDst || !lockedSrc) { + return; + } + Texture& srctex = *lockedSrc; + Texture& dsttex = *lockedDst; + assert(srctex.bpp() == 4); + assert(dsttex.bpp() == 4); + + IntRect srcReq = + IntRect{srcX, srcY, srcX + srcWidth, srcY + srcHeight} - srctex.offset; + IntRect dstReq = + IntRect{dstX, dstY, dstX + dstWidth, dstY + dstHeight} - dsttex.offset; + if (srcReq.is_empty() || dstReq.is_empty()) { + return; + } + + // Compute clip rect as relative to the dstReq, as that's the same coords + // as used for the sampling bounds. + IntRect clipRect = {clipX - dstX, clipY - dstY, clipX - dstX + clipWidth, + clipY - dstY + clipHeight}; + // Ensure we have rows of at least 2 pixels when using the linear filter to + // avoid overreading the row. Force X flips onto the linear filter for now + // until scale_blit supports it. + bool useLinear = + srctex.width >= 2 && + (flipX || (!srcReq.same_size(dstReq) && filter == GL_LINEAR)); + + if (opaque) { + if (useLinear) { + linear_blit<false>(srctex, srcReq, dsttex, dstReq, flipX, flipY, + clipRect); + } else { + scale_blit<false>(srctex, srcReq, dsttex, dstReq, flipY, clipRect); + } + } else { + if (useLinear) { + linear_blit<true>(srctex, srcReq, dsttex, dstReq, flipX, flipY, clipRect); + } else { + scale_blit<true>(srctex, srcReq, dsttex, dstReq, flipY, clipRect); + } + } +} + +} // extern "C" + +// Saturated add helper for YUV conversion. Supported platforms have intrinsics +// to do this natively, but support a slower generic fallback just in case. +static inline V8<int16_t> addsat(V8<int16_t> x, V8<int16_t> y) { +#if USE_SSE2 + return _mm_adds_epi16(x, y); +#elif USE_NEON + return vqaddq_s16(x, y); +#else + auto r = x + y; + // An overflow occurred if the signs of both inputs x and y did not differ + // but yet the sign of the result did differ. + auto overflow = (~(x ^ y) & (r ^ x)) >> 15; + // If there was an overflow, we need to choose the appropriate limit to clamp + // to depending on whether or not the inputs are negative. + auto limit = (x >> 15) ^ 0x7FFF; + // If we didn't overflow, just use the result, and otherwise, use the limit. + return (~overflow & r) | (overflow & limit); +#endif +} + +// Interleave and packing helper for YUV conversion. During transform by the +// color matrix, the color components are de-interleaved as this format is +// usually what comes out of the planar YUV textures. The components thus need +// to be interleaved before finally getting packed to BGRA format. Alpha is +// forced to be opaque. +static inline PackedRGBA8 packYUV(V8<int16_t> gg, V8<int16_t> br) { + return pack(bit_cast<WideRGBA8>(zip(br, gg))) | + PackedRGBA8{0, 0, 0, 255, 0, 0, 0, 255, 0, 0, 0, 255, 0, 0, 0, 255}; +} + +// clang-format off +// Supports YUV color matrixes of the form: +// [R] [1.1643835616438356, 0.0, rv ] [Y - 16] +// [G] = [1.1643835616438358, -gu, -gv ] x [U - 128] +// [B] [1.1643835616438356, bu, 0.0 ] [V - 128] +// We must be able to multiply a YUV input by a matrix coefficient ranging as +// high as ~2.2 in the U/V cases, where U/V can be signed values between -128 +// and 127. The largest fixed-point representation we can thus support without +// overflowing 16 bit integers leaves us 6 bits of fractional precision while +// also supporting a sign bit. The closest representation of the Y coefficient +// ~1.164 in this precision is 74.5/2^6 which is common to all color spaces +// we support. Conversions can still sometimes overflow the precision and +// require clamping back into range, so we use saturated additions to do this +// efficiently at no extra cost. +// clang-format on +struct YUVMatrix { + // These constants are loaded off the "this" pointer via relative addressing + // modes and should be about as quick to load as directly addressed SIMD + // constant memory. + + V8<int16_t> br_uvCoeffs; // biased by 6 bits [b_from_u, r_from_v, repeats] + V8<int16_t> gg_uvCoeffs; // biased by 6 bits [g_from_u, g_from_v, repeats] + V8<uint16_t> yCoeffs; // biased by 7 bits + V8<int16_t> yBias; // 0 or 16 + V8<int16_t> uvBias; // 128 + V8<int16_t> br_yMask; + + // E.g. rec709-narrow: + // [ 1.16, 0, 1.79, -0.97 ] + // [ 1.16, -0.21, -0.53, 0.30 ] + // [ 1.16, 2.11, 0, -1.13 ] + // = + // [ yScale, 0, r_from_v ] ([Y ] ) + // [ yScale, g_from_u, g_from_v ] x ([cb] - ycbcr_bias ) + // [ yScale, b_from_u, 0 ] ([cr] ) + static YUVMatrix From(const vec3_scalar& ycbcr_bias, + const mat3_scalar& rgb_from_debiased_ycbcr, + int rescale_factor = 0) { + assert(ycbcr_bias.z == ycbcr_bias.y); + + const auto rgb_from_y = rgb_from_debiased_ycbcr[0].y; + assert(rgb_from_debiased_ycbcr[0].x == rgb_from_debiased_ycbcr[0].z); + + int16_t br_from_y_mask = -1; + if (rgb_from_debiased_ycbcr[0].x == 0.0) { + // gbr-identity matrix? + assert(rgb_from_debiased_ycbcr[0].x == 0); + assert(rgb_from_debiased_ycbcr[0].y >= 1); + assert(rgb_from_debiased_ycbcr[0].z == 0); + + assert(rgb_from_debiased_ycbcr[1].x == 0); + assert(rgb_from_debiased_ycbcr[1].y == 0); + assert(rgb_from_debiased_ycbcr[1].z >= 1); + + assert(rgb_from_debiased_ycbcr[2].x >= 1); + assert(rgb_from_debiased_ycbcr[2].y == 0); + assert(rgb_from_debiased_ycbcr[2].z == 0); + + assert(ycbcr_bias.x == 0); + assert(ycbcr_bias.y == 0); + assert(ycbcr_bias.z == 0); + + br_from_y_mask = 0; + } else { + assert(rgb_from_debiased_ycbcr[0].x == rgb_from_y); + } + + assert(rgb_from_debiased_ycbcr[1].x == 0.0); + const auto g_from_u = rgb_from_debiased_ycbcr[1].y; + const auto b_from_u = rgb_from_debiased_ycbcr[1].z; + + const auto r_from_v = rgb_from_debiased_ycbcr[2].x; + const auto g_from_v = rgb_from_debiased_ycbcr[2].y; + assert(rgb_from_debiased_ycbcr[2].z == 0.0); + + return YUVMatrix({ycbcr_bias.x, ycbcr_bias.y}, rgb_from_y, br_from_y_mask, + r_from_v, g_from_u, g_from_v, b_from_u, rescale_factor); + } + + // Convert matrix coefficients to fixed-point representation. If the matrix + // has a rescaling applied to it, then we need to take care to undo the + // scaling so that we can convert the coefficients to fixed-point range. The + // bias still requires shifting to apply the rescaling. The rescaling will be + // applied to the actual YCbCr sample data later by manually shifting it + // before applying this matrix. + YUVMatrix(vec2_scalar yuv_bias, double yCoeff, int16_t br_yMask_, double rv, + double gu, double gv, double bu, int rescale_factor = 0) + : br_uvCoeffs(zip(I16(int16_t(bu * (1 << (6 - rescale_factor)) + 0.5)), + I16(int16_t(rv * (1 << (6 - rescale_factor)) + 0.5)))), + gg_uvCoeffs( + zip(I16(-int16_t(-gu * (1 << (6 - rescale_factor)) + + 0.5)), // These are negative coeffs, so + // round them away from zero + I16(-int16_t(-gv * (1 << (6 - rescale_factor)) + 0.5)))), + yCoeffs(uint16_t(yCoeff * (1 << (6 + 1 - rescale_factor)) + 0.5)), + // We have a +0.5 fudge-factor for -ybias. + // Without this, we get white=254 not 255. + // This approximates rounding rather than truncation during `gg >>= 6`. + yBias(int16_t(((yuv_bias.x * 255 * yCoeff) - 0.5) * (1 << 6))), + uvBias(int16_t(yuv_bias.y * (255 << rescale_factor) + 0.5)), + br_yMask(br_yMask_) { + assert(yuv_bias.x >= 0); + assert(yuv_bias.y >= 0); + assert(yCoeff > 0); + assert(br_yMask_ == 0 || br_yMask_ == -1); + assert(bu > 0); + assert(rv > 0); + assert(gu <= 0); + assert(gv <= 0); + assert(rescale_factor <= 6); + } + + ALWAYS_INLINE PackedRGBA8 convert(V8<int16_t> yy, V8<int16_t> uv) const { + // We gave ourselves an extra bit (7 instead of 6) of bias to give us some + // extra precision for the more-sensitive y scaling. + // Note that we have to use an unsigned multiply with a 2x scale to + // represent a fractional scale and to avoid shifting with the sign bit. + + // Note: if you subtract the bias before multiplication, we see more + // underflows. This could be fixed by an unsigned subsat. + yy = bit_cast<V8<int16_t>>((bit_cast<V8<uint16_t>>(yy) * yCoeffs) >> 1); + yy -= yBias; + + // Compute [B] = [yCoeff*Y + bu*U + 0*V] + // [R] [yCoeff*Y + 0*U + rv*V] + uv -= uvBias; + auto br = br_uvCoeffs * uv; + br = addsat(yy & br_yMask, br); + br >>= 6; + + // Compute G = yCoeff*Y + gu*U + gv*V + // First calc [gu*U, gv*V, ...]: + auto gg = gg_uvCoeffs * uv; + // Then cross the streams to get `gu*U + gv*V`: + gg = addsat(gg, bit_cast<V8<int16_t>>(bit_cast<V4<uint32_t>>(gg) >> 16)); + // Add the other parts: + gg = addsat(yy, gg); // This is the part that needs the most headroom + // usually. In particular, ycbcr(255,255,255) hugely + // saturates. + gg >>= 6; + + // Interleave B/R and G values. Force alpha (high-gg half) to opaque. + return packYUV(gg, br); + } +}; + +// Helper function for textureLinearRowR8 that samples horizontal taps and +// combines them based on Y fraction with next row. +template <typename S> +static ALWAYS_INLINE V8<int16_t> linearRowTapsR8(S sampler, I32 ix, + int32_t offsety, + int32_t stridey, + int16_t fracy) { + uint8_t* buf = (uint8_t*)sampler->buf + offsety; + auto a0 = unaligned_load<V2<uint8_t>>(&buf[ix.x]); + auto b0 = unaligned_load<V2<uint8_t>>(&buf[ix.y]); + auto c0 = unaligned_load<V2<uint8_t>>(&buf[ix.z]); + auto d0 = unaligned_load<V2<uint8_t>>(&buf[ix.w]); + auto abcd0 = CONVERT(combine(a0, b0, c0, d0), V8<int16_t>); + buf += stridey; + auto a1 = unaligned_load<V2<uint8_t>>(&buf[ix.x]); + auto b1 = unaligned_load<V2<uint8_t>>(&buf[ix.y]); + auto c1 = unaligned_load<V2<uint8_t>>(&buf[ix.z]); + auto d1 = unaligned_load<V2<uint8_t>>(&buf[ix.w]); + auto abcd1 = CONVERT(combine(a1, b1, c1, d1), V8<int16_t>); + abcd0 += ((abcd1 - abcd0) * fracy) >> 7; + return abcd0; +} + +// Optimized version of textureLinearPackedR8 for Y R8 texture. This assumes +// constant Y and returns a duplicate of the result interleaved with itself +// to aid in later YUV transformation. +template <typename S> +static inline V8<int16_t> textureLinearRowR8(S sampler, I32 ix, int32_t offsety, + int32_t stridey, int16_t fracy) { + assert(sampler->format == TextureFormat::R8); + + // Calculate X fraction and clamp X offset into range. + I32 fracx = ix; + ix >>= 7; + fracx = ((fracx & (ix >= 0)) | (ix > int32_t(sampler->width) - 2)) & 0x7F; + ix = clampCoord(ix, sampler->width - 1); + + // Load the sample taps and combine rows. + auto abcd = linearRowTapsR8(sampler, ix, offsety, stridey, fracy); + + // Unzip the result and do final horizontal multiply-add base on X fraction. + auto abcdl = SHUFFLE(abcd, abcd, 0, 0, 2, 2, 4, 4, 6, 6); + auto abcdh = SHUFFLE(abcd, abcd, 1, 1, 3, 3, 5, 5, 7, 7); + abcdl += ((abcdh - abcdl) * CONVERT(fracx, I16).xxyyzzww) >> 7; + + // The final result is the packed values interleaved with a duplicate of + // themselves. + return abcdl; +} + +// Optimized version of textureLinearPackedR8 for paired U/V R8 textures. +// Since the two textures have the same dimensions and stride, the addressing +// math can be shared between both samplers. This also allows a coalesced +// multiply in the final stage by packing both U/V results into a single +// operation. +template <typename S> +static inline V8<int16_t> textureLinearRowPairedR8(S sampler, S sampler2, + I32 ix, int32_t offsety, + int32_t stridey, + int16_t fracy) { + assert(sampler->format == TextureFormat::R8 && + sampler2->format == TextureFormat::R8); + assert(sampler->width == sampler2->width && + sampler->height == sampler2->height); + assert(sampler->stride == sampler2->stride); + + // Calculate X fraction and clamp X offset into range. + I32 fracx = ix; + ix >>= 7; + fracx = ((fracx & (ix >= 0)) | (ix > int32_t(sampler->width) - 2)) & 0x7F; + ix = clampCoord(ix, sampler->width - 1); + + // Load the sample taps for the first sampler and combine rows. + auto abcd = linearRowTapsR8(sampler, ix, offsety, stridey, fracy); + + // Load the sample taps for the second sampler and combine rows. + auto xyzw = linearRowTapsR8(sampler2, ix, offsety, stridey, fracy); + + // We are left with a result vector for each sampler with values for adjacent + // pixels interleaved together in each. We need to unzip these values so that + // we can do the final horizontal multiply-add based on the X fraction. + auto abcdxyzwl = SHUFFLE(abcd, xyzw, 0, 8, 2, 10, 4, 12, 6, 14); + auto abcdxyzwh = SHUFFLE(abcd, xyzw, 1, 9, 3, 11, 5, 13, 7, 15); + abcdxyzwl += ((abcdxyzwh - abcdxyzwl) * CONVERT(fracx, I16).xxyyzzww) >> 7; + + // The final result is the packed values for the first sampler interleaved + // with the packed values for the second sampler. + return abcdxyzwl; +} + +// Casting to int loses some precision while stepping that can offset the +// image, so shift the values by some extra bits of precision to minimize +// this. We support up to 16 bits of image size, 7 bits of quantization, +// and 1 bit for sign, which leaves 8 bits left for extra precision. +const int STEP_BITS = 8; + +// Optimized version of textureLinearPackedR8 for Y R8 texture with +// half-resolution paired U/V R8 textures. This allows us to more efficiently +// pack YUV samples into vectors to substantially reduce math operations even +// further. +template <bool BLEND> +static inline void upscaleYUV42R8(uint32_t* dest, int span, uint8_t* yRow, + I32 yU, int32_t yDU, int32_t yStrideV, + int16_t yFracV, uint8_t* cRow1, + uint8_t* cRow2, I32 cU, int32_t cDU, + int32_t cStrideV, int16_t cFracV, + const YUVMatrix& colorSpace) { + // As much as possible try to utilize the fact that we're only using half + // the UV samples to combine Y and UV samples into single vectors. Here we + // need to initialize several useful vector quantities for stepping fractional + // offsets. For the UV samples, we take the average of the first+second and + // third+fourth samples in a chunk which conceptually correspond to offsets + // 0.5 and 1.5 (in 0..2 range). This allows us to reconstruct intermediate + // samples 0.25, 0.75, 1.25, and 1.75 later. X fraction is shifted over into + // the top 7 bits of an unsigned short so that we can mask off the exact + // fractional bits we need to blend merely by right shifting them into + // position. + cU = (cU.xzxz + cU.ywyw) >> 1; + auto ycFracX = CONVERT(combine(yU, cU), V8<uint16_t>) + << (16 - (STEP_BITS + 7)); + auto ycFracDX = combine(I16(yDU), I16(cDU)) << (16 - (STEP_BITS + 7)); + auto ycFracV = combine(I16(yFracV), I16(cFracV)); + I32 yI = yU >> (STEP_BITS + 7); + I32 cI = cU >> (STEP_BITS + 7); + // Load initial combined YUV samples for each row and blend them. + auto ycSrc0 = + CONVERT(combine(unaligned_load<V4<uint8_t>>(&yRow[yI.x]), + combine(unaligned_load<V2<uint8_t>>(&cRow1[cI.x]), + unaligned_load<V2<uint8_t>>(&cRow2[cI.x]))), + V8<int16_t>); + auto ycSrc1 = CONVERT( + combine(unaligned_load<V4<uint8_t>>(&yRow[yI.x + yStrideV]), + combine(unaligned_load<V2<uint8_t>>(&cRow1[cI.x + cStrideV]), + unaligned_load<V2<uint8_t>>(&cRow2[cI.x + cStrideV]))), + V8<int16_t>); + auto ycSrc = ycSrc0 + (((ycSrc1 - ycSrc0) * ycFracV) >> 7); + + // Here we shift in results from the next sample while caching results from + // the previous sample. This allows us to reduce the multiplications in the + // inner loop down to only two since we just need to blend the new samples + // horizontally and then vertically once each. + for (uint32_t* end = dest + span; dest < end; dest += 4) { + yU += yDU; + I32 yIn = yU >> (STEP_BITS + 7); + cU += cDU; + I32 cIn = cU >> (STEP_BITS + 7); + // Load combined YUV samples for the next chunk on each row and blend them. + auto ycSrc0n = + CONVERT(combine(unaligned_load<V4<uint8_t>>(&yRow[yIn.x]), + combine(unaligned_load<V2<uint8_t>>(&cRow1[cIn.x]), + unaligned_load<V2<uint8_t>>(&cRow2[cIn.x]))), + V8<int16_t>); + auto ycSrc1n = CONVERT( + combine(unaligned_load<V4<uint8_t>>(&yRow[yIn.x + yStrideV]), + combine(unaligned_load<V2<uint8_t>>(&cRow1[cIn.x + cStrideV]), + unaligned_load<V2<uint8_t>>(&cRow2[cIn.x + cStrideV]))), + V8<int16_t>); + auto ycSrcn = ycSrc0n + (((ycSrc1n - ycSrc0n) * ycFracV) >> 7); + + // The source samples for the chunk may not match the actual tap offsets. + // Since we're upscaling, we know the tap offsets fall within all the + // samples in a 4-wide chunk. Since we can't rely on PSHUFB or similar, + // instead we do laborious shuffling here for the Y samples and then the UV + // samples. + auto yshuf = lowHalf(ycSrc); + auto yshufn = + SHUFFLE(yshuf, yIn.x == yI.w ? lowHalf(ycSrcn).yyyy : lowHalf(ycSrcn), + 1, 2, 3, 4); + if (yI.y == yI.x) { + yshuf = yshuf.xxyz; + yshufn = yshufn.xxyz; + } + if (yI.z == yI.y) { + yshuf = yshuf.xyyz; + yshufn = yshufn.xyyz; + } + if (yI.w == yI.z) { + yshuf = yshuf.xyzz; + yshufn = yshufn.xyzz; + } + + auto cshuf = highHalf(ycSrc); + auto cshufn = + SHUFFLE(cshuf, cIn.x == cI.y ? highHalf(ycSrcn).yyww : highHalf(ycSrcn), + 1, 4, 3, 6); + if (cI.y == cI.x) { + cshuf = cshuf.xxzz; + cshufn = cshufn.xxzz; + } + + // After shuffling, combine the Y and UV samples back into a single vector + // for blending. Shift X fraction into position as unsigned to mask off top + // bits and get rid of low bits to avoid multiplication overflow. + auto yuvPx = combine(yshuf, cshuf); + yuvPx += ((combine(yshufn, cshufn) - yuvPx) * + bit_cast<V8<int16_t>>(ycFracX >> (16 - 7))) >> + 7; + + // Cache the new samples as the current samples on the next iteration. + ycSrc = ycSrcn; + ycFracX += ycFracDX; + yI = yIn; + cI = cIn; + + // De-interleave the Y and UV results. We need to average the UV results + // to produce values for intermediate samples. Taps for UV were collected at + // offsets 0.5 and 1.5, such that if we take a quarter of the difference + // (1.5-0.5)/4, subtract it from even samples, and add it to odd samples, + // we can estimate samples 0.25, 0.75, 1.25, and 1.75. + auto yPx = SHUFFLE(yuvPx, yuvPx, 0, 0, 1, 1, 2, 2, 3, 3); + auto uvPx = SHUFFLE(yuvPx, yuvPx, 4, 6, 4, 6, 5, 7, 5, 7) + + ((SHUFFLE(yuvPx, yuvPx, 4, 6, 5, 7, 4, 6, 5, 7) - + SHUFFLE(yuvPx, yuvPx, 5, 7, 4, 6, 5, 7, 4, 6)) >> + 2); + + commit_blend_span<BLEND>(dest, colorSpace.convert(yPx, uvPx)); + } +} + +// This is the inner loop driver of CompositeYUV that processes an axis-aligned +// YUV span, dispatching based on appropriate format and scaling. This is also +// reused by blendYUV to accelerate some cases of texture sampling in the +// shader. +template <bool BLEND = false> +static void linear_row_yuv(uint32_t* dest, int span, sampler2DRect samplerY, + const vec2_scalar& srcUV, float srcDU, + sampler2DRect samplerU, sampler2DRect samplerV, + const vec2_scalar& chromaUV, float chromaDU, + int colorDepth, const YUVMatrix& colorSpace) { + // Calculate varying and constant interp data for Y plane. + I32 yU = cast(init_interp(srcUV.x, srcDU) * (1 << STEP_BITS)); + int32_t yV = int32_t(srcUV.y); + + // Calculate varying and constant interp data for chroma planes. + I32 cU = cast(init_interp(chromaUV.x, chromaDU) * (1 << STEP_BITS)); + int32_t cV = int32_t(chromaUV.y); + + // We need to skip 4 pixels per chunk. + int32_t yDU = int32_t((4 << STEP_BITS) * srcDU); + int32_t cDU = int32_t((4 << STEP_BITS) * chromaDU); + + if (samplerY->width < 2 || samplerU->width < 2) { + // If the source row has less than 2 pixels, it's not safe to use a linear + // filter because it may overread the row. Just convert the single pixel + // with nearest filtering and fill the row with it. + Float yuvF = {texelFetch(samplerY, ivec2(srcUV)).x.x, + texelFetch(samplerU, ivec2(chromaUV)).x.x, + texelFetch(samplerV, ivec2(chromaUV)).x.x, 1.0f}; + // If this is an HDR LSB format, we need to renormalize the result. + if (colorDepth > 8) { + int rescaleFactor = 16 - colorDepth; + yuvF *= float(1 << rescaleFactor); + } + I16 yuv = CONVERT(round_pixel(yuvF), I16); + commit_solid_span<BLEND>( + dest, + unpack(colorSpace.convert(V8<int16_t>(yuv.x), + zip(I16(yuv.y), I16(yuv.z)))), + span); + } else if (samplerY->format == TextureFormat::R16) { + // Sample each YUV plane, rescale it to fit in low 8 bits of word, and + // then transform them by the appropriate color space. + assert(colorDepth > 8); + // Need to right shift the sample by the amount of bits over 8 it + // occupies. On output from textureLinearUnpackedR16, we have lost 1 bit + // of precision at the low end already, hence 1 is subtracted from the + // color depth. + int rescaleBits = (colorDepth - 1) - 8; + for (; span >= 4; span -= 4) { + auto yPx = + textureLinearUnpackedR16(samplerY, ivec2(yU >> STEP_BITS, yV)) >> + rescaleBits; + auto uPx = + textureLinearUnpackedR16(samplerU, ivec2(cU >> STEP_BITS, cV)) >> + rescaleBits; + auto vPx = + textureLinearUnpackedR16(samplerV, ivec2(cU >> STEP_BITS, cV)) >> + rescaleBits; + commit_blend_span<BLEND>( + dest, colorSpace.convert(zip(yPx, yPx), zip(uPx, vPx))); + dest += 4; + yU += yDU; + cU += cDU; + } + if (span > 0) { + // Handle any remaining pixels... + auto yPx = + textureLinearUnpackedR16(samplerY, ivec2(yU >> STEP_BITS, yV)) >> + rescaleBits; + auto uPx = + textureLinearUnpackedR16(samplerU, ivec2(cU >> STEP_BITS, cV)) >> + rescaleBits; + auto vPx = + textureLinearUnpackedR16(samplerV, ivec2(cU >> STEP_BITS, cV)) >> + rescaleBits; + commit_blend_span<BLEND>( + dest, colorSpace.convert(zip(yPx, yPx), zip(uPx, vPx)), span); + } + } else { + assert(samplerY->format == TextureFormat::R8); + assert(colorDepth == 8); + + // Calculate varying and constant interp data for Y plane. + int16_t yFracV = yV & 0x7F; + yV >>= 7; + int32_t yOffsetV = clampCoord(yV, samplerY->height) * samplerY->stride; + int32_t yStrideV = + yV >= 0 && yV < int32_t(samplerY->height) - 1 ? samplerY->stride : 0; + + // Calculate varying and constant interp data for chroma planes. + int16_t cFracV = cV & 0x7F; + cV >>= 7; + int32_t cOffsetV = clampCoord(cV, samplerU->height) * samplerU->stride; + int32_t cStrideV = + cV >= 0 && cV < int32_t(samplerU->height) - 1 ? samplerU->stride : 0; + + // If we're sampling the UV planes at half the resolution of the Y plane, + // then try to use half resolution fast-path. + if (yDU >= cDU && cDU > 0 && yDU <= (4 << (STEP_BITS + 7)) && + cDU <= (2 << (STEP_BITS + 7))) { + // Ensure that samples don't fall outside of the valid bounds of each + // planar texture. Step until the initial X coordinates are positive. + for (; (yU.x < 0 || cU.x < 0) && span >= 4; span -= 4) { + auto yPx = textureLinearRowR8(samplerY, yU >> STEP_BITS, yOffsetV, + yStrideV, yFracV); + auto uvPx = textureLinearRowPairedR8( + samplerU, samplerV, cU >> STEP_BITS, cOffsetV, cStrideV, cFracV); + commit_blend_span<BLEND>(dest, colorSpace.convert(yPx, uvPx)); + dest += 4; + yU += yDU; + cU += cDU; + } + // Calculate the number of aligned chunks that we can step inside the + // bounds of each planar texture without overreading. + int inside = min( + min((((int(samplerY->width) - 4) << (STEP_BITS + 7)) - yU.x) / yDU, + (((int(samplerU->width) - 4) << (STEP_BITS + 7)) - cU.x) / cDU) * + 4, + span & ~3); + if (inside > 0) { + uint8_t* yRow = (uint8_t*)samplerY->buf + yOffsetV; + uint8_t* cRow1 = (uint8_t*)samplerU->buf + cOffsetV; + uint8_t* cRow2 = (uint8_t*)samplerV->buf + cOffsetV; + upscaleYUV42R8<BLEND>(dest, inside, yRow, yU, yDU, yStrideV, yFracV, + cRow1, cRow2, cU, cDU, cStrideV, cFracV, + colorSpace); + span -= inside; + dest += inside; + yU += (inside / 4) * yDU; + cU += (inside / 4) * cDU; + } + // If there are any remaining chunks that weren't inside, handle them + // below. + } + for (; span >= 4; span -= 4) { + // Sample each YUV plane and then transform them by the appropriate + // color space. + auto yPx = textureLinearRowR8(samplerY, yU >> STEP_BITS, yOffsetV, + yStrideV, yFracV); + auto uvPx = textureLinearRowPairedR8(samplerU, samplerV, cU >> STEP_BITS, + cOffsetV, cStrideV, cFracV); + commit_blend_span<BLEND>(dest, colorSpace.convert(yPx, uvPx)); + dest += 4; + yU += yDU; + cU += cDU; + } + if (span > 0) { + // Handle any remaining pixels... + auto yPx = textureLinearRowR8(samplerY, yU >> STEP_BITS, yOffsetV, + yStrideV, yFracV); + auto uvPx = textureLinearRowPairedR8(samplerU, samplerV, cU >> STEP_BITS, + cOffsetV, cStrideV, cFracV); + commit_blend_span<BLEND>(dest, colorSpace.convert(yPx, uvPx), span); + } + } +} + +static void linear_convert_yuv(Texture& ytex, Texture& utex, Texture& vtex, + const YUVMatrix& rgbFromYcbcr, int colorDepth, + const IntRect& srcReq, Texture& dsttex, + const IntRect& dstReq, bool invertX, + bool invertY, const IntRect& clipRect) { + // Compute valid dest bounds + IntRect dstBounds = dsttex.sample_bounds(dstReq); + dstBounds.intersect(clipRect); + // Check if sampling bounds are empty + if (dstBounds.is_empty()) { + return; + } + // Initialize samplers for source textures + sampler2DRect_impl sampler[3]; + init_sampler(&sampler[0], ytex); + init_sampler(&sampler[1], utex); + init_sampler(&sampler[2], vtex); + + // Compute source UVs + vec2_scalar srcUV(srcReq.x0, srcReq.y0); + vec2_scalar srcDUV(float(srcReq.width()) / dstReq.width(), + float(srcReq.height()) / dstReq.height()); + if (invertX) { + // Advance to the end of the row and flip the step. + srcUV.x += srcReq.width(); + srcDUV.x = -srcDUV.x; + } + // Inverted Y must step downward along source rows + if (invertY) { + srcUV.y += srcReq.height(); + srcDUV.y = -srcDUV.y; + } + // Skip to clamped source start + srcUV += srcDUV * (vec2_scalar(dstBounds.x0, dstBounds.y0) + 0.5f); + // Calculate separate chroma UVs for chroma planes with different scale + vec2_scalar chromaScale(float(utex.width) / ytex.width, + float(utex.height) / ytex.height); + vec2_scalar chromaUV = srcUV * chromaScale; + vec2_scalar chromaDUV = srcDUV * chromaScale; + // Scale UVs by lerp precision. If the row has only 1 pixel, then don't + // quantize so that we can use nearest filtering instead to avoid overreads. + if (ytex.width >= 2 && utex.width >= 2) { + srcUV = linearQuantize(srcUV, 128); + srcDUV *= 128.0f; + chromaUV = linearQuantize(chromaUV, 128); + chromaDUV *= 128.0f; + } + // Calculate dest pointer from clamped offsets + int destStride = dsttex.stride(); + char* dest = dsttex.sample_ptr(dstReq, dstBounds); + int span = dstBounds.width(); + for (int rows = dstBounds.height(); rows > 0; rows--) { + linear_row_yuv((uint32_t*)dest, span, &sampler[0], srcUV, srcDUV.x, + &sampler[1], &sampler[2], chromaUV, chromaDUV.x, colorDepth, + rgbFromYcbcr); + dest += destStride; + srcUV.y += srcDUV.y; + chromaUV.y += chromaDUV.y; + } +} + +// - +// This section must match gfx/2d/Types.h + +enum class YUVRangedColorSpace : uint8_t { + BT601_Narrow = 0, + BT601_Full, + BT709_Narrow, + BT709_Full, + BT2020_Narrow, + BT2020_Full, + GbrIdentity, +}; + +// - +// This section must match yuv.glsl + +vec4_scalar get_ycbcr_zeros_ones(const YUVRangedColorSpace color_space, + const GLuint color_depth) { + // For SWGL's 8bpc-only pipeline, our extra care here probably doesn't matter. + // However, technically e.g. 10-bit achromatic zero for cb and cr is + // (128 << 2) / ((1 << 10) - 1) = 512 / 1023, which != 128 / 255, and affects + // our matrix values subtly. Maybe not enough to matter? But it's the most + // correct thing to do. + // Unlike the glsl version, our texture samples are u8([0,255]) not + // u16([0,1023]) though. + switch (color_space) { + case YUVRangedColorSpace::BT601_Narrow: + case YUVRangedColorSpace::BT709_Narrow: + case YUVRangedColorSpace::BT2020_Narrow: { + auto extra_bit_count = color_depth - 8; + vec4_scalar zo = { + float(16 << extra_bit_count), + float(128 << extra_bit_count), + float(235 << extra_bit_count), + float(240 << extra_bit_count), + }; + float all_bits = (1 << color_depth) - 1; + zo /= all_bits; + return zo; + } + + case YUVRangedColorSpace::BT601_Full: + case YUVRangedColorSpace::BT709_Full: + case YUVRangedColorSpace::BT2020_Full: { + const auto narrow = + get_ycbcr_zeros_ones(YUVRangedColorSpace::BT601_Narrow, color_depth); + return {0.0, narrow.y, 1.0, 1.0}; + } + + case YUVRangedColorSpace::GbrIdentity: + break; + } + return {0.0, 0.0, 1.0, 1.0}; +} + +constexpr mat3_scalar RgbFromYuv_Rec601 = { + {1.00000, 1.00000, 1.00000}, + {0.00000, -0.17207, 0.88600}, + {0.70100, -0.35707, 0.00000}, +}; +constexpr mat3_scalar RgbFromYuv_Rec709 = { + {1.00000, 1.00000, 1.00000}, + {0.00000, -0.09366, 0.92780}, + {0.78740, -0.23406, 0.00000}, +}; +constexpr mat3_scalar RgbFromYuv_Rec2020 = { + {1.00000, 1.00000, 1.00000}, + {0.00000, -0.08228, 0.94070}, + {0.73730, -0.28568, 0.00000}, +}; +constexpr mat3_scalar RgbFromYuv_GbrIdentity = { + {0, 1, 0}, + {0, 0, 1}, + {1, 0, 0}, +}; + +inline mat3_scalar get_rgb_from_yuv(const YUVRangedColorSpace color_space) { + switch (color_space) { + case YUVRangedColorSpace::BT601_Narrow: + case YUVRangedColorSpace::BT601_Full: + return RgbFromYuv_Rec601; + case YUVRangedColorSpace::BT709_Narrow: + case YUVRangedColorSpace::BT709_Full: + return RgbFromYuv_Rec709; + case YUVRangedColorSpace::BT2020_Narrow: + case YUVRangedColorSpace::BT2020_Full: + return RgbFromYuv_Rec2020; + case YUVRangedColorSpace::GbrIdentity: + break; + } + return RgbFromYuv_GbrIdentity; +} + +struct YcbcrInfo final { + vec3_scalar ycbcr_bias; + mat3_scalar rgb_from_debiased_ycbcr; +}; + +inline YcbcrInfo get_ycbcr_info(const YUVRangedColorSpace color_space, + GLuint color_depth) { + // SWGL always does 8bpc math, so don't scale the matrix for 10bpc! + color_depth = 8; + + const auto zeros_ones = get_ycbcr_zeros_ones(color_space, color_depth); + const auto zeros = vec2_scalar{zeros_ones.x, zeros_ones.y}; + const auto ones = vec2_scalar{zeros_ones.z, zeros_ones.w}; + const auto scale = 1.0f / (ones - zeros); + + const auto rgb_from_yuv = get_rgb_from_yuv(color_space); + const mat3_scalar yuv_from_debiased_ycbcr = { + {scale.x, 0, 0}, + {0, scale.y, 0}, + {0, 0, scale.y}, + }; + + YcbcrInfo ret; + ret.ycbcr_bias = {zeros.x, zeros.y, zeros.y}; + ret.rgb_from_debiased_ycbcr = rgb_from_yuv * yuv_from_debiased_ycbcr; + return ret; +} + +// - + +extern "C" { + +// Extension for compositing a YUV surface represented by separate YUV planes +// to a BGRA destination. The supplied color space is used to determine the +// transform from YUV to BGRA after sampling. +void CompositeYUV(LockedTexture* lockedDst, LockedTexture* lockedY, + LockedTexture* lockedU, LockedTexture* lockedV, + YUVRangedColorSpace colorSpace, GLuint colorDepth, GLint srcX, + GLint srcY, GLsizei srcWidth, GLsizei srcHeight, GLint dstX, + GLint dstY, GLsizei dstWidth, GLsizei dstHeight, + GLboolean flipX, GLboolean flipY, GLint clipX, GLint clipY, + GLsizei clipWidth, GLsizei clipHeight) { + if (!lockedDst || !lockedY || !lockedU || !lockedV) { + return; + } + if (colorSpace > YUVRangedColorSpace::GbrIdentity) { + assert(false); + return; + } + const auto ycbcrInfo = get_ycbcr_info(colorSpace, colorDepth); + const auto rgbFromYcbcr = + YUVMatrix::From(ycbcrInfo.ycbcr_bias, ycbcrInfo.rgb_from_debiased_ycbcr); + + Texture& ytex = *lockedY; + Texture& utex = *lockedU; + Texture& vtex = *lockedV; + Texture& dsttex = *lockedDst; + // All YUV planes must currently be represented by R8 or R16 textures. + // The chroma (U/V) planes must have matching dimensions. + assert(ytex.bpp() == utex.bpp() && ytex.bpp() == vtex.bpp()); + assert((ytex.bpp() == 1 && colorDepth == 8) || + (ytex.bpp() == 2 && colorDepth > 8)); + // assert(ytex.width == utex.width && ytex.height == utex.height); + assert(utex.width == vtex.width && utex.height == vtex.height); + assert(ytex.offset == utex.offset && ytex.offset == vtex.offset); + assert(dsttex.bpp() == 4); + + IntRect srcReq = + IntRect{srcX, srcY, srcX + srcWidth, srcY + srcHeight} - ytex.offset; + IntRect dstReq = + IntRect{dstX, dstY, dstX + dstWidth, dstY + dstHeight} - dsttex.offset; + if (srcReq.is_empty() || dstReq.is_empty()) { + return; + } + + // Compute clip rect as relative to the dstReq, as that's the same coords + // as used for the sampling bounds. + IntRect clipRect = {clipX - dstX, clipY - dstY, clipX - dstX + clipWidth, + clipY - dstY + clipHeight}; + // For now, always use a linear filter path that would be required for + // scaling. Further fast-paths for non-scaled video might be desirable in the + // future. + linear_convert_yuv(ytex, utex, vtex, rgbFromYcbcr, colorDepth, srcReq, dsttex, + dstReq, flipX, flipY, clipRect); +} + +} // extern "C" |