/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "WebGLContext.h"

#include "GLContext.h"
#include "GLScreenBuffer.h"
#include "WebGLFormats.h"
#include "WebGLFramebuffer.h"
#include "WebGLRenderbuffer.h"
#include "WebGLTexture.h"

namespace mozilla {

void WebGLContext::Clear(GLbitfield mask) {
  const FuncScope funcScope(*this, "clear");
  if (IsContextLost()) return;

  uint32_t m = mask & (LOCAL_GL_COLOR_BUFFER_BIT | LOCAL_GL_DEPTH_BUFFER_BIT |
                       LOCAL_GL_STENCIL_BUFFER_BIT);
  if (mask != m) return ErrorInvalidValue("Invalid mask bits.");

  if (mask == 0) {
    GenerateWarning("Calling gl.clear(0) has no effect.");
  } else if (mRasterizerDiscardEnabled) {
    GenerateWarning(
        "Calling gl.clear() with RASTERIZER_DISCARD enabled has no effects.");
  }

  if (mask & LOCAL_GL_COLOR_BUFFER_BIT && mBoundDrawFramebuffer) {
    for (const auto& cur : mBoundDrawFramebuffer->ColorDrawBuffers()) {
      const auto imageInfo = cur->GetImageInfo();
      if (!imageInfo || !imageInfo->mFormat) continue;

      if (imageInfo->mFormat->format->baseType !=
          webgl::TextureBaseType::Float) {
        ErrorInvalidOperation(
            "Color draw buffers must be floating-point"
            " or fixed-point. (normalized (u)ints)");
        return;
      }
    }
  }

  if (!BindCurFBForDraw()) return;

  auto driverMask = mask;
  if (!mBoundDrawFramebuffer) {
    if (mNeedsFakeNoDepth) {
      driverMask &= ~LOCAL_GL_DEPTH_BUFFER_BIT;
    }
    if (mNeedsFakeNoStencil) {
      driverMask &= ~LOCAL_GL_STENCIL_BUFFER_BIT;
    }
  }

  const ScopedDrawCallWrapper wrapper(*this);
  gl->fClear(driverMask);
}

static GLfloat GLClampFloat(GLfloat val) {
  if (val < 0.0) return 0.0;

  if (val > 1.0) return 1.0;

  return val;
}

void WebGLContext::ClearColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a) {
  const FuncScope funcScope(*this, "clearColor");
  if (IsContextLost()) return;

  if (IsExtensionEnabled(WebGLExtensionID::EXT_color_buffer_float)) {
    MOZ_ASSERT(IsExtensionExplicit(WebGLExtensionID::EXT_color_buffer_float));

  } else if (IsExtensionEnabled(
                 WebGLExtensionID::EXT_color_buffer_half_float) ||
             IsExtensionEnabled(WebGLExtensionID::WEBGL_color_buffer_float)) {
    const bool explict =
        (IsExtensionExplicit(WebGLExtensionID::EXT_color_buffer_half_float) ||
         IsExtensionExplicit(WebGLExtensionID::WEBGL_color_buffer_float));
    const bool wouldHaveClamped =
        (r != GLClampFloat(r) || g != GLClampFloat(g) || b != GLClampFloat(b) ||
         a != GLClampFloat(a));
    if (!explict && wouldHaveClamped) {
      if (IsExtensionEnabled(WebGLExtensionID::EXT_color_buffer_half_float)) {
        WarnIfImplicit(WebGLExtensionID::EXT_color_buffer_half_float);
      } else if (IsExtensionEnabled(
                     WebGLExtensionID::WEBGL_color_buffer_float)) {
        WarnIfImplicit(WebGLExtensionID::WEBGL_color_buffer_float);
      }
    }
  } else {
    r = GLClampFloat(r);
    g = GLClampFloat(g);
    b = GLClampFloat(b);
    a = GLClampFloat(a);
  }

  gl->fClearColor(r, g, b, a);

  mColorClearValue[0] = r;
  mColorClearValue[1] = g;
  mColorClearValue[2] = b;
  mColorClearValue[3] = a;
}

void WebGLContext::ClearDepth(GLclampf v) {
  const FuncScope funcScope(*this, "clearDepth");
  if (IsContextLost()) return;

  mDepthClearValue = GLClampFloat(v);
  gl->fClearDepth(mDepthClearValue);
}

void WebGLContext::ClearStencil(GLint v) {
  const FuncScope funcScope(*this, "clearStencil");
  if (IsContextLost()) return;

  mStencilClearValue = v;
  gl->fClearStencil(v);
}

void WebGLContext::ColorMask(const Maybe<GLuint> i, const uint8_t mask) {
  const FuncScope funcScope(*this, "colorMask");
  if (IsContextLost()) return;

  if (i) {
    MOZ_RELEASE_ASSERT(
        IsExtensionEnabled(WebGLExtensionID::OES_draw_buffers_indexed));
    const auto limit = MaxValidDrawBuffers();
    if (*i >= limit) {
      ErrorInvalidValue("`index` (%u) must be < %s (%u)", *i,
                        "MAX_DRAW_BUFFERS", limit);
      return;
    }
    if (*i == 0) {
      mColorWriteMask0 = mask;
    }
    mColorWriteMaskNonzero[*i] = bool(mask);
  } else {
    mColorWriteMask0 = mask;
    if (mask) {
      mColorWriteMaskNonzero.set();
    } else {
      mColorWriteMaskNonzero.reset();
    }
  }

  DoColorMask(i, mask);
}

void WebGLContext::DepthMask(WebGLboolean b) {
  const FuncScope funcScope(*this, "depthMask");
  if (IsContextLost()) return;

  mDepthWriteMask = b;
  gl->fDepthMask(b);
}

void WebGLContext::DrawBuffers(const std::vector<GLenum>& buffers) {
  const FuncScope funcScope(*this, "drawBuffers");
  if (IsContextLost()) return;

  if (mBoundDrawFramebuffer) {
    mBoundDrawFramebuffer->DrawBuffers(buffers);
    return;
  }

  // GLES 3.0.4 p186:
  // "If the GL is bound to the default framebuffer, then `n` must be 1 and the
  //  constant must be BACK or NONE. [...] If DrawBuffers is supplied with a
  //  constant other than BACK and NONE, or with a value of `n` other than 1,
  //  the error INVALID_OPERATION is generated."
  if (buffers.size() != 1) {
    ErrorInvalidOperation(
        "For the default framebuffer, `buffers` must have a"
        " length of 1.");
    return;
  }

  switch (buffers[0]) {
    case LOCAL_GL_NONE:
    case LOCAL_GL_BACK:
      break;

    default:
      ErrorInvalidOperation(
          "For the default framebuffer, `buffers[0]` must be"
          " BACK or NONE.");
      return;
  }

  mDefaultFB_DrawBuffer0 = buffers[0];
  // Don't actually set it.
}

void WebGLContext::StencilMaskSeparate(GLenum face, GLuint mask) {
  const FuncScope funcScope(*this, "stencilMaskSeparate");
  if (IsContextLost()) return;

  if (!ValidateFaceEnum(face)) return;

  switch (face) {
    case LOCAL_GL_FRONT_AND_BACK:
      mStencilWriteMaskFront = mask;
      mStencilWriteMaskBack = mask;
      break;
    case LOCAL_GL_FRONT:
      mStencilWriteMaskFront = mask;
      break;
    case LOCAL_GL_BACK:
      mStencilWriteMaskBack = mask;
      break;
  }

  gl->fStencilMaskSeparate(face, mask);
}

}  // namespace mozilla