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// Copyright 2016 The Emscripten Authors. All rights reserved.
// Emscripten is available under two separate licenses, the MIT license and the
// University of Illinois/NCSA Open Source License. Both these licenses can be
// found in the LICENSE file.
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <emscripten/emscripten.h>
#include <emscripten/html5.h>
#define GL_RGBA32F 0x8814
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context;
int main()
{
EmscriptenWebGLContextAttributes attrs;
emscripten_webgl_init_context_attributes(&attrs);
attrs.enableExtensionsByDefault = true;
EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context("#canvas", &attrs);
emscripten_webgl_make_context_current(context);
// Test what the return values of GL_IMPLEMENTATION_COLOR_READ_TYPE and GL_IMPLEMENTATION_COLOR_READ_FORMAT are.
GLint type = -1, format = -1;
glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE, &type);
printf("GL_IMPLEMENTATION_COLOR_READ_TYPE for FBO 0: 0x%x\n", type);
glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT, &format);
printf("GL_IMPLEMENTATION_COLOR_READ_FORMAT for FBO 0: 0x%x\n", format);
// Try glReadPixels() in that format.
unsigned char data[16];
glReadPixels(0, 0, 1, 1, format, type, &data);
assert(glGetError() == 0 && "glReadPixels of FBO 0 in implementation defined format failed");
// Try glReadPixels() in the format that is mandated to work by the spec.
glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &data);
assert(glGetError() == 0 && "glReadPixels of FBO 0 in GL_RGBA+GL_UNSIGNED_BYTE format failed");
// Test the same with a floating point render target bound.
GLuint fbo;
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
GLuint rb;
glGenRenderbuffers(1, &rb);
glBindRenderbuffer(GL_RENDERBUFFER, rb);
glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA32F, 512, 512);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, rb);
assert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE);
glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE, &type);
printf("GL_IMPLEMENTATION_COLOR_READ_TYPE for FBO with float renderbuffer: 0x%x\n", type);
glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT, &format);
printf("GL_IMPLEMENTATION_COLOR_READ_FORMAT for FBO with float renderbuffer: 0x%x\n", format);
// Try glReadPixels() in that format.
if (format == GL_RGBA && type == GL_UNSIGNED_BYTE)
{
printf("Oops, WebGL implementation returns an implementation defined color type(==GL_UNSIGNED_BYTE) & format(==GL_RGBA) that should "
"not be possible to be used to sample WebGL floating point color renderbuffer according to WEBGL_color_buffer_float.\n");
}
while (glGetError() != 0);
glReadPixels(0, 0, 1, 1, format, type, &data);
if (glGetError() != 0) printf("glReadPixels of FBO with floating point color renderbuffer in implementation defined format failed");
// Try glReadPixels() in the format that is mandated to work by the spec. WEBGL_color_buffer_float says
// that GL_RGBA and GL_UNSIGNED_BYTE no longer work but instead GL_RGBA and GL_FLOAT must be used.
glReadPixels(0, 0, 1, 1, GL_RGBA, GL_FLOAT, &data);
assert(glGetError() == 0 && "glReadPixels of FBO with floating point color renderbuffer in GL_RGBA+GL_FLOAT format failed");
return 0;
}
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