dom/canvas/WebGLExtensionDrawBuffers.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   4  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "WebGLContext.h"
   7 #include "WebGLExtensions.h"
   8 #include "mozilla/dom/WebGLRenderingContextBinding.h"
   9 #include "WebGLTexture.h"
  10 #include "WebGLRenderbuffer.h"
  11 #include "WebGLFramebuffer.h"
  12 #include "GLContext.h"
  13
  14 #include <algorithm>
  15
  16 using namespace mozilla;
  17 using namespace gl;
  18
  19 WebGLExtensionDrawBuffers::WebGLExtensionDrawBuffers(WebGLContext* context)
  20     : WebGLExtensionBase(context)
  21 {
  22     GLint maxColorAttachments = 0;
  23     GLint maxDrawBuffers = 0;
  24
  25     gl::GLContext* gl = context->GL();
  26
  27     context->MakeContextCurrent();
  28
  29     gl->fGetIntegerv(LOCAL_GL_MAX_COLOR_ATTACHMENTS, &maxColorAttachments);
  30     gl->fGetIntegerv(LOCAL_GL_MAX_DRAW_BUFFERS, &maxDrawBuffers);
  31
  32     // WEBGL_draw_buffers specifications don't give a maximal value reachable by MAX_COLOR_ATTACHMENTS.
  33     maxColorAttachments = std::min(maxColorAttachments, GLint(WebGLContext::kMaxColorAttachments));
  34
  35     if (context->MinCapabilityMode())
  36     {
  37         maxColorAttachments = std::min(maxColorAttachments, GLint(sMinColorAttachments));
  38     }
  39
  40     // WEBGL_draw_buffers specifications request MAX_COLOR_ATTACHMENTS >= MAX_DRAW_BUFFERS.
  41     maxDrawBuffers = std::min(maxDrawBuffers, GLint(maxColorAttachments));
  42
  43     context->mGLMaxColorAttachments = maxColorAttachments;
  44     context->mGLMaxDrawBuffers = maxDrawBuffers;
  45 }
  46
  47 WebGLExtensionDrawBuffers::~WebGLExtensionDrawBuffers()
  48 {
  49 }
  50
  51 void WebGLExtensionDrawBuffers::DrawBuffersWEBGL(const dom::Sequence<GLenum>& buffers)
  52 {
  53     if (mIsLost)
  54         return mContext->ErrorInvalidOperation("drawBuffersWEBGL: Extension is lost.");
  55
  56     mContext->DrawBuffers(buffers);
  57 }
  58
  59 bool WebGLExtensionDrawBuffers::IsSupported(const WebGLContext* context)
  60 {
  61     gl::GLContext * gl = context->GL();
  62
  63     if (!gl->IsSupported(GLFeature::draw_buffers)) {
  64         return false;
  65     }
  66
  67     GLint supportedColorAttachments = 0;
  68     GLint supportedDrawBuffers = 0;
  69
  70     context->MakeContextCurrent();
  71
  72     gl->fGetIntegerv(LOCAL_GL_MAX_COLOR_ATTACHMENTS, &supportedColorAttachments);
  73     gl->fGetIntegerv(LOCAL_GL_MAX_COLOR_ATTACHMENTS, &supportedDrawBuffers);
  74
  75     if (size_t(supportedColorAttachments) < sMinColorAttachments){
  76         // WEBGL_draw_buffers specifications request for 4 color attachments at least.
  77         return false;
  78     }
  79
  80     if (size_t(supportedDrawBuffers) < sMinDrawBuffers){
  81         return false;
  82     }
  83
  84     return true;
  85 }
  86
  87 IMPL_WEBGL_EXTENSION_GOOP(WebGLExtensionDrawBuffers)