/* 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/. */ #include shared,clip_shared,ellipse varying highp vec4 vLocalPos; #ifdef WR_FEATURE_FAST_PATH flat varying mediump vec3 vClipParams; // xy = box size, z = radius #else flat varying highp vec4 vClipCenter_Radius_TL; flat varying highp vec4 vClipCenter_Radius_TR; flat varying highp vec4 vClipCenter_Radius_BL; flat varying highp vec4 vClipCenter_Radius_BR; flat varying highp vec3 vClipPlane_TL; flat varying highp vec3 vClipPlane_TR; flat varying highp vec3 vClipPlane_BL; flat varying highp vec3 vClipPlane_BR; #endif // Clip mode. Packed in to a vector to work around bug 1630356. flat varying mediump vec2 vClipMode; #ifdef WR_VERTEX_SHADER PER_INSTANCE in vec2 aClipLocalPos; PER_INSTANCE in vec4 aClipLocalRect; PER_INSTANCE in float aClipMode; PER_INSTANCE in vec4 aClipRect_TL; PER_INSTANCE in vec4 aClipRadii_TL; PER_INSTANCE in vec4 aClipRect_TR; PER_INSTANCE in vec4 aClipRadii_TR; PER_INSTANCE in vec4 aClipRect_BL; PER_INSTANCE in vec4 aClipRadii_BL; PER_INSTANCE in vec4 aClipRect_BR; PER_INSTANCE in vec4 aClipRadii_BR; struct ClipMaskInstanceRect { ClipMaskInstanceCommon base; vec2 local_pos; }; ClipMaskInstanceRect fetch_clip_item() { ClipMaskInstanceRect cmi; cmi.base = fetch_clip_item_common(); cmi.local_pos = aClipLocalPos; return cmi; } struct ClipRect { RectWithEndpoint rect; float mode; }; struct ClipCorner { RectWithEndpoint rect; vec4 outer_inner_radius; }; struct ClipData { ClipRect rect; ClipCorner top_left; ClipCorner top_right; ClipCorner bottom_left; ClipCorner bottom_right; }; ClipData fetch_clip() { ClipData clip; clip.rect = ClipRect(RectWithEndpoint(aClipLocalRect.xy, aClipLocalRect.zw), aClipMode); clip.top_left = ClipCorner(RectWithEndpoint(aClipRect_TL.xy, aClipRect_TL.zw), aClipRadii_TL); clip.top_right = ClipCorner(RectWithEndpoint(aClipRect_TR.xy, aClipRect_TR.zw), aClipRadii_TR); clip.bottom_left = ClipCorner(RectWithEndpoint(aClipRect_BL.xy, aClipRect_BL.zw), aClipRadii_BL); clip.bottom_right = ClipCorner(RectWithEndpoint(aClipRect_BR.xy, aClipRect_BR.zw), aClipRadii_BR); return clip; } void main(void) { ClipMaskInstanceRect cmi = fetch_clip_item(); Transform clip_transform = fetch_transform(cmi.base.clip_transform_id); Transform prim_transform = fetch_transform(cmi.base.prim_transform_id); ClipData clip = fetch_clip(); RectWithEndpoint local_rect = clip.rect.rect; vec2 diff = cmi.local_pos - local_rect.p0; local_rect.p0 = cmi.local_pos; local_rect.p1 += diff; ClipVertexInfo vi = write_clip_tile_vertex( local_rect, prim_transform, clip_transform, cmi.base.sub_rect, cmi.base.task_origin, cmi.base.screen_origin, cmi.base.device_pixel_scale ); vClipMode.x = clip.rect.mode; vLocalPos = vi.local_pos; #ifdef WR_FEATURE_FAST_PATH // If the radii are all uniform, we can use a much simpler 2d // signed distance function to get a rounded rect clip. vec2 half_size = 0.5 * rect_size(local_rect); float radius = clip.top_left.outer_inner_radius.x; vLocalPos.xy -= (half_size + cmi.local_pos) * vi.local_pos.w; vClipParams = vec3(half_size - vec2(radius), radius); #else RectWithEndpoint clip_rect = local_rect; vec2 r_tl = clip.top_left.outer_inner_radius.xy; vec2 r_tr = clip.top_right.outer_inner_radius.xy; vec2 r_br = clip.bottom_right.outer_inner_radius.xy; vec2 r_bl = clip.bottom_left.outer_inner_radius.xy; vClipCenter_Radius_TL = vec4(clip_rect.p0 + r_tl, inverse_radii_squared(r_tl)); vClipCenter_Radius_TR = vec4(clip_rect.p1.x - r_tr.x, clip_rect.p0.y + r_tr.y, inverse_radii_squared(r_tr)); vClipCenter_Radius_BR = vec4(clip_rect.p1 - r_br, inverse_radii_squared(r_br)); vClipCenter_Radius_BL = vec4(clip_rect.p0.x + r_bl.x, clip_rect.p1.y - r_bl.y, inverse_radii_squared(r_bl)); // We need to know the half-spaces of the corners separate from the center // and radius. We compute a point that falls on the diagonal (which is just // an inner vertex pushed out along one axis, but not on both) to get the // plane offset of the half-space. We also compute the direction vector of // the half-space, which is a perpendicular vertex (-y,x) of the vector of // the diagonal. We leave the scales of the vectors unchanged. vec2 n_tl = -r_tl.yx; vec2 n_tr = vec2(r_tr.y, -r_tr.x); vec2 n_br = r_br.yx; vec2 n_bl = vec2(-r_bl.y, r_bl.x); vClipPlane_TL = vec3(n_tl, dot(n_tl, vec2(clip_rect.p0.x, clip_rect.p0.y + r_tl.y))); vClipPlane_TR = vec3(n_tr, dot(n_tr, vec2(clip_rect.p1.x - r_tr.x, clip_rect.p0.y))); vClipPlane_BR = vec3(n_br, dot(n_br, vec2(clip_rect.p1.x, clip_rect.p1.y - r_br.y))); vClipPlane_BL = vec3(n_bl, dot(n_bl, vec2(clip_rect.p0.x + r_bl.x, clip_rect.p1.y))); #endif } #endif #ifdef WR_FRAGMENT_SHADER #ifdef WR_FEATURE_FAST_PATH // See http://www.iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm float sd_box(in vec2 pos, in vec2 box_size) { vec2 d = abs(pos) - box_size; return length(max(d, vec2(0.0))) + min(max(d.x,d.y), 0.0); } float sd_rounded_box(in vec2 pos, in vec2 box_size, in float radius) { return sd_box(pos, box_size) - radius; } #endif void main(void) { vec2 local_pos = vLocalPos.xy / vLocalPos.w; float aa_range = compute_aa_range(local_pos); #ifdef WR_FEATURE_FAST_PATH float dist = sd_rounded_box(local_pos, vClipParams.xy, vClipParams.z); #else float dist = distance_to_rounded_rect( local_pos, vClipPlane_TL, vClipCenter_Radius_TL, vClipPlane_TR, vClipCenter_Radius_TR, vClipPlane_BR, vClipCenter_Radius_BR, vClipPlane_BL, vClipCenter_Radius_BL, vTransformBounds ); #endif // Compute AA for the given dist and range. float alpha = distance_aa(aa_range, dist); // Select alpha or inverse alpha depending on clip in/out. float final_alpha = mix(alpha, 1.0 - alpha, vClipMode.x); float final_final_alpha = vLocalPos.w > 0.0 ? final_alpha : 0.0; oFragColor = vec4(final_final_alpha, 0.0, 0.0, 1.0); } #ifdef SWGL_DRAW_SPAN // Currently the cs_clip_rectangle shader is slow because it always evaluates // the corner ellipse segments and the rectangle AA for every fragment the // shader is run on. To alleviate this for now with SWGL, this essentially // implements a rounded-rectangle span rasterizer inside the span shader. The // motivation is that we can separate out the parts of the span which are fully // opaque and fully transparent, outputting runs of fixed color in those areas, // while only evaluating the ellipse segments and AA in the smaller outlying // parts of the span that actually need it. // The shader conceptually represents a rounded rectangle as an inner octagon // (8 half-spaces) bounding the opaque region and an outer octagon bounding the // curve and AA parts. Everything outside is transparent. The line of the span // is intersected with half-spaces, looking for interior spans that minimally // intersect the half-spaces (start max, end min). In the ideal case we hit a // start corner ellipse segment and an end corner ellipse segment, rendering // the two curves on the ends with an opaque run in between, outputting clear // for any transparent runs before and after the start and end curves. // This is slightly complicated by the fact that the results here must agree // with the main results of the fragment shader, in case SWGL has to fall back // to the main fragment shader for any reason. So, we make an effort to handle // both ways of operating - the uniform radius fast-path and the varying radius // slow-path. void swgl_drawSpanR8() { // Perspective is not supported. if (swgl_interpStep(vLocalPos).w != 0.0) { return; } // If the span is completely outside the Z-range and clipped out, just // output clear so we don't need to consider invalid W in the rest of the // shader. float w = swgl_forceScalar(vLocalPos.w); if (w <= 0.0) { swgl_commitSolidR8(0.0); return; } // To start, we evaluate the rounded-rectangle in local space relative to // the local-space position. This will be interpolated across the span to // track whether we intersect any half-spaces. w = 1.0 / w; vec2 local_pos = vLocalPos.xy * w; vec2 local_pos0 = swgl_forceScalar(local_pos); vec2 local_step = swgl_interpStep(vLocalPos).xy * w; float step_scale = max(dot(local_step, local_step), 1.0e-6); // Get the local-space AA range. This range represents 1/fwidth(local_pos), // essentially the scale of how much local-space maps to an AA pixel. We // need to know the inverse, how much local-space we traverse per AA pixel // pixel step. We then scale this to represent the amount of span steps // traversed per AA pixel step. float aa_range = compute_aa_range(local_pos); float aa_margin = inversesqrt(aa_range * aa_range * step_scale); // We need to know the bounds of the aligned rectangle portion of the rrect // in local-space. If we're using the fast-path, this is specified as the // inner bounding-box half-width of the rrect and the uniform outer radius // of the corners in vClipParams, which we map to the outer bounding-box. // For the general case, we have already stored the outer bounding box in // vTransformBounds. #ifdef WR_FEATURE_FAST_PATH vec4 clip_rect = vec4(-vClipParams.xy - vClipParams.z, vClipParams.xy + vClipParams.z); #else vec4 clip_rect = vTransformBounds; #endif // We need to compute the local-space distance to the bounding box and then // figure out how many processing steps that maps to. If we are stepping in // a negative direction on an axis, we need to swap the sides of the box // which we consider as the start or end. If there is no local-space step // on an axis (i.e. constant Y), we need to take care to force the steps to // either the start or end of the span depending on if we are inside or // outside of the bounding box. vec4 clip_dist = mix(clip_rect, clip_rect.zwxy, lessThan(local_step, vec2(0.0)).xyxy) - local_pos0.xyxy; clip_dist = mix(1.0e6 * step(0.0, clip_dist), clip_dist * recip(local_step).xyxy, notEqual(local_step, vec2(0.0)).xyxy); // Initially, the opaque region is bounded by the further start intersect // with the bounding box and the nearest end intersect with the bounding // box. float opaque_start = max(clip_dist.x, clip_dist.y); float opaque_end = min(clip_dist.z, clip_dist.w); float aa_start = opaque_start; float aa_end = opaque_end; // Here we actually intersect with the half-space of the corner. We get the // plane distance of the local-space position from the diagonal bounding // ellipse segment from the opaque region. The half-space is defined by the // direction vector of the plane and an offset point that falls on the // dividing line (which is a vertex on the corner box, which is actually on // the outer radius of the bounding box, but not a corner vertex). This // distance is positive if on the curve side and negative if on the inner // opaque region. If we are on the curve side, we need to verify we are // traveling in direction towards the opaque region so that we will // eventually intersect the diagonal so we can calculate when the start // corner segment will end, otherwise we are going away from the rrect. // If we are inside the opaque interior, we need to verify we are traveling // in direction towards the curve, so that we can calculate when the end // corner segment will start. Further, if we intersect, we calculate the // offset of the outer octagon where AA starts from the inner octagon of // where the opaque region starts using the apex vector (which is transpose // of the half-space's direction). // // We need to intersect the corner ellipse segments. Significantly, we need // to know where the apex of the ellipse segment is and how far to push the // outer diagonal of the octagon from the inner diagonal. The position of // the inner diagonal simply runs diagonal across the corner box and has a // constant offset from vertex on the inner bounding box. The apex also has // a constant offset along the opposite diagonal relative to the diagonal // intersect which is 1/sqrt(2) - 0.5 assuming unit length for the diagonal. // We then need to project the vector to the apex onto the local-space step // scale, but we do this with reference to the normal vector of the diagonal // using dot(normal, apex) / dot(normal, local_step), where the apex vector // is (0.7071 - 0.5) * abs(normal).yx * sign(normal). vec3 start_plane = vec3(1.0e6); vec3 end_plane = vec3(1.0e6); // plane is assumed to be a vec3 with normal in (X, Y) and offset in Z. #define CLIP_CORNER(plane, info) do { \ float dist = dot(local_pos0, plane.xy) - plane.z; \ float scale = -dot(local_step, plane.xy); \ if (scale >= 0.0) { \ if (dist > opaque_start * scale) { \ SET_CORNER(start_corner, info); \ start_plane = plane; \ float inv_scale = recip(max(scale, 1.0e-6)); \ opaque_start = dist * inv_scale; \ float apex = (0.7071 - 0.5) * 2.0 * abs(plane.x * plane.y); \ aa_start = opaque_start - apex * inv_scale; \ } \ } else if (dist > opaque_end * scale) { \ SET_CORNER(end_corner, info); \ end_plane = plane; \ float inv_scale = recip(min(scale, -1.0e-6)); \ opaque_end = dist * inv_scale; \ float apex = (0.7071 - 0.5) * 2.0 * abs(plane.x * plane.y); \ aa_end = opaque_end - apex * inv_scale; \ } \ } while (false) #ifdef WR_FEATURE_FAST_PATH // For the fast-path, we only have the half-width of the inner bounding // box. We need to map this to points that fall on the diagonal of the // half-space for each corner. To do this we just need to push out the // vertex in the right direction on a single axis, leaving the other // unchanged. // However, since the corner radii are all the same, and since the local // origin of each ellipse is assumed to be at (0, 0), the plane offset // of the half-space is the same for each case. So given a corner offset // of (x+z, y) and a vector of (z, z), the dot product becomes: // (x+z)*z + y*z == x*z + y*z + z*z // The direction vector of the corner half-space has constant length, // but just needs an appropriate direction set. float offset = (vClipParams.x + vClipParams.y + vClipParams.z) * vClipParams.z; vec3 plane_tl = vec3(-vClipParams.zz, offset); vec3 plane_tr = vec3(vClipParams.z, -vClipParams.z, offset); vec3 plane_br = vec3(vClipParams.zz, offset); vec3 plane_bl = vec3(-vClipParams.z, vClipParams.z, offset); #define SET_CORNER(corner, info) // Clip against the corner half-spaces. CLIP_CORNER(plane_tl, ); CLIP_CORNER(plane_tr, ); CLIP_CORNER(plane_br, ); CLIP_CORNER(plane_bl, ); // Later we need to calculate distance AA for both corners and the // outer bounding rect. For the fast-path, this is all done inside // sd_rounded_box. #define AA_RECT(local_pos) \ sd_rounded_box(local_pos, vClipParams.xy, vClipParams.z) #else // For the general case, we need to remember which of the actual start // and end corners we intersect, so that we can evaluate the curve AA // against only those corners rather than having to try against all 4 // corners for both sides of the span. Initialize these values so that // if no corner is intersected, they will just zero the AA. vec4 start_corner = vec4(vec2(1.0e6), vec2(1.0)); vec4 end_corner = vec4(vec2(1.0e6), vec2(1.0)); #define SET_CORNER(corner, info) corner = info // Clip against the corner half-spaces. We have already computed the // corner half-spaces in the vertex shader. CLIP_CORNER(vClipPlane_TL, vClipCenter_Radius_TL); CLIP_CORNER(vClipPlane_TR, vClipCenter_Radius_TR); CLIP_CORNER(vClipPlane_BR, vClipCenter_Radius_BR); CLIP_CORNER(vClipPlane_BL, vClipCenter_Radius_BL); // Later we need to calculate distance AA for both corners and the // outer bounding rect. For the general case, we need to explicitly // evaluate either the ellipse segment distance or the rect distance. #define AA_RECT(local_pos) \ signed_distance_rect(local_pos, vTransformBounds.xy, vTransformBounds.zw) #define AA_CORNER(local_pos, corner) \ distance_to_ellipse_approx(local_pos - corner.xy, corner.zw, 1.0) #endif // Pad the AA region by a margin, as the intersections take place assuming // pixel centers, but AA actually starts half a pixel away from the center. // If the AA region narrows to nothing, be careful not to inflate so much // that we start processing AA for fragments that don't need it. aa_margin = max(aa_margin - max(aa_start - aa_end, 0.0), 0.0); aa_start -= aa_margin; aa_end += aa_margin; // Compute the thresholds at which we need to transition between various // segments of the span, from fully transparent outside to the start of // the outer octagon where AA starts, from there to where the inner opaque // octagon starts, from there to where the opaque inner octagon ends and // AA starts again, to finally where the outer octagon/AA ends and we're // back to fully transparent. These thresholds are just flipped offsets // from the start of the span so we can compare against the remaining // span length which automatically deducts as we commit fragments. ivec4 steps = ivec4(clamp( swgl_SpanLength - swgl_StepSize * vec4(floor(aa_start), ceil(opaque_start), floor(opaque_end), ceil(aa_end)), 0.0, swgl_SpanLength)); int aa_start_len = steps.x; int opaque_start_len = steps.y; int opaque_end_len = steps.z; int aa_end_len = steps.w; // Output fully clear while we're outside the AA region. if (swgl_SpanLength > aa_start_len) { int num_aa = swgl_SpanLength - aa_start_len; swgl_commitPartialSolidR8(num_aa, vClipMode.x); local_pos += float(num_aa / swgl_StepSize) * local_step; } #ifdef AA_CORNER if (start_plane.x < 1.0e5) { // We're now in the outer octagon which requires AA. Evaluate the corner // distance of the start corner here and output AA for it. Before we hit // the actual opaque inner octagon, we have a transitional step where the // diagonal might intersect mid-way through the step. We have consider // either the corner or rect distance depending on which side we're on. while (swgl_SpanLength > opaque_start_len) { float alpha = distance_aa(aa_range, dot(local_pos, start_plane.xy) > start_plane.z ? AA_CORNER(local_pos, start_corner) : AA_RECT(local_pos)); swgl_commitColorR8(mix(alpha, 1.0 - alpha, vClipMode.x)); local_pos += local_step; } } #endif // If there's no start corner, just do rect AA until opaque. while (swgl_SpanLength > opaque_start_len) { float alpha = distance_aa(aa_range, AA_RECT(local_pos)); swgl_commitColorR8(mix(alpha, 1.0 - alpha, vClipMode.x)); local_pos += local_step; } // Now we're finally in the opaque inner octagon part of the span. Just // output a solid run. if (swgl_SpanLength > opaque_end_len) { int num_opaque = swgl_SpanLength - opaque_end_len; swgl_commitPartialSolidR8(num_opaque, 1.0 - vClipMode.x); local_pos += float(num_opaque / swgl_StepSize) * local_step; } #ifdef AA_CORNER if (end_plane.x < 1.0e5) { // Finally we're in the AA region on the other side, inside the outer // octagon again. Just evaluate the distance to the end corner and // compute AA for it. We're leaving the opaque inner octagon, but like // before, we have to be careful we're not dealing with a step partially // intersected by the end corner's diagonal. Check which side we are on // and use either the corner or rect distance as appropriate. while (swgl_SpanLength > aa_end_len) { float alpha = distance_aa(aa_range, dot(local_pos, end_plane.xy) > end_plane.z ? AA_CORNER(local_pos, end_corner) : AA_RECT(local_pos)); swgl_commitColorR8(mix(alpha, 1.0 - alpha, vClipMode.x)); local_pos += local_step; } } #endif // If there's no end corner, just do rect AA until clear. while (swgl_SpanLength > aa_end_len) { float alpha = distance_aa(aa_range, AA_RECT(local_pos)); swgl_commitColorR8(mix(alpha, 1.0 - alpha, vClipMode.x)); local_pos += local_step; } // We're now outside the outer AA octagon on the other side. Just output // fully clear. if (swgl_SpanLength > 0) { swgl_commitPartialSolidR8(swgl_SpanLength, vClipMode.x); } } #endif #endif