OpenGL ES 3.0-Multiple Render Targets

最新推荐文章于 2025-05-07 14:36:59 发布

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MRT，多渲染对象，用来将场景同时渲染到多个目标中去。

1. 设置4个渲染目标

bool initFramebuffer(int w, int h)
{
	glGenRenderbuffers( 1, &g_DepthRenderBuffer);
    glBindRenderbuffer( GL_RENDERBUFFER, g_DepthRenderBuffer );
    glRenderbufferStorage( GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, w, h);
	CHECK_GL_ERROR

	glGenFramebuffers(1, &g_FrameBuffer);
	glBindFramebuffer(GL_FRAMEBUFFER, g_FrameBuffer);
	CHECK_GL_ERROR

	for(int i = 0; i <= 3; ++i)
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0+i, GL_TEXTURE_2D, g_Texture2Ds[i], 0);

	glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,g_DepthRenderBuffer );
	CHECK_GL_ERROR

	GLenum DrawBuffers[4];
	DrawBuffers[0] = GL_COLOR_ATTACHMENT0;
	DrawBuffers[1] = GL_COLOR_ATTACHMENT1;
	DrawBuffers[2] = GL_COLOR_ATTACHMENT2;
	DrawBuffers[3] = GL_COLOR_ATTACHMENT3;

	glDrawBuffers(4, DrawBuffers);
	CHECK_GL_ERROR

	if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
		return false;

//	glBindFramebuffer( GL_FRAMEBUFFER, 0 );
//	glBindRenderbuffer( GL_RENDERBUFFER, 0 );
	 
	return true;
}

2. 渲染到4个渲染目标

#version 300 es

#ifdef GL_FRAGMENT_PRECISION_HIGH								
precision highp float;										
#else												
precision mediump float;									
#endif	

#define FRAG_RED		0
#define FRAG_GREEN		1
#define FRAG_BLUE		2
#define FRAG_RGBA		3


in	vec3 vColor;
in  vec3 vPos;

layout(location = FRAG_RED) out vec4 Red;
layout(location = FRAG_GREEN) out vec4 Green;
layout(location = FRAG_BLUE) out vec4 Blue;
layout(location = FRAG_RGBA) out vec4 RGBA;

void main()
{
	vec4 Color = vec4(vColor, 1.0) * 0.7f;
	float light = 1.0 / (length(vPos)+0.5f);
	Red = vec4(Color.r * light, 0, 0, 1);
	Green = vec4(0, Color.g * light, 0, 1);
	Blue = vec4(0, 0, Color.b * light,1);
	RGBA = Color * light;
}