我已经努力尝试让这个工作在过去几天中,但我真的开始变得绝望了。如果您有任何建议,我将非常感激。
我一直在尝试做以下事情:
- 将场景渲染到FBO - 使用glsl着色器模糊附加的纹理 - 将结果纹理渲染到屏幕对齐的四边形上
问题是:
如果我启用片段着色器(水平模糊),我确实会在我的四边形上获得一个模糊的图像,但仅在第一帧或更多时,之后就全黑了。
我怀疑我传递纹理给我的着色器的方式有问题:
我一直在尝试做以下事情:
- 将场景渲染到FBO - 使用glsl着色器模糊附加的纹理 - 将结果纹理渲染到屏幕对齐的四边形上
问题是:
如果我启用片段着色器(水平模糊),我确实会在我的四边形上获得一个模糊的图像,但仅在第一帧或更多时,之后就全黑了。
我怀疑我传递纹理给我的着色器的方式有问题:
horizontalBlurVertex.enable();
horizontalBlurFragment.enable();
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, fboTexture);
glUniform1i(glGetUniformLocation(horizontalBlurFragment.program, "RTScene"), 0);
编辑:
还有一条信息: 如果我删除glUniform1i(glGetUniformLocation(horizontalBlurFragment.program,“RTScene”),0);我得到完全相同的结果。这意味着我的着色器根本没有获得任何纹理数据。来源:
顶点着色器:
varying vec2 vTexCoord;
void main(void)
{
gl_FrontColor = gl_Color;
gl_Position = ftransform();
vec2 Pos;
Pos = sign(gl_Vertex.xy);
gl_Position = vec4(Pos, 0.0, 1.0);
vTexCoord = Pos * 0.5 + 0.5;
}
片段着色器:
uniform sampler2D RTScene;
varying vec2 vTexCoord;
const float blurSize = 1.0/800.0;
const float weightSum = 70.0 + 2.0 * (1.0 + 8.0 + 28.0 + 56.0);
void main(void)
{
vec4 sum = vec4(0.0);
sum += texture2D(RTScene, vec2(vTexCoord.x - 4.0*blurSize, vTexCoord.y)) * 1.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x - 3.0*blurSize, vTexCoord.y)) * 8.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x - 2.0*blurSize, vTexCoord.y)) * 28.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x - blurSize, vTexCoord.y)) * 56.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x, vTexCoord.y)) * 70.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x + blurSize, vTexCoord.y)) * 56.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x + 2.0*blurSize, vTexCoord.y)) * 28.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x + 3.0*blurSize, vTexCoord.y)) * 8.0 / weightSum;
sum += texture2D(RTScene, vec2(vTexCoord.x + 4.0*blurSize, vTexCoord.y)) * 1.0 / weightSum;
gl_FragColor = sum;
}
渲染到帧缓冲对象:
//handels
GLuint fbo, fboTexture, fboDepthbuffer;
// generate namespace for the frame buffer, colorbuffer and depthbuffer
glGenFramebuffersEXT(1, &fbo);
glGenTextures(1, &fboTexture);
glGenRenderbuffersEXT(1, &fboDepthbuffer);
//switch to our fbo so we can bind stuff to it
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
//create the colorbuffer texture and attach it to the frame buffer
glGenTextures(1, &fboTexture);
glBindTexture(GL_TEXTURE_2D, fboTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, fboTexture, 0);
// create a render buffer as our depthbuffer and attach it
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fboDepthbuffer);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, fboDepthbuffer);
// Go back to regular frame buffer rendering
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
glPushAttrib(GL_VIEWPORT_BIT);
glViewport(0, 0, width, height);
glPushMatrix();
glBegin(GL_QUADS);
glNormal3f(0.0, 0.0, 1.0);
glColor3f(1.0f, 1.0f, 0.0f);
glVertex3f(-0.1, 0.1, -1.0);
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(0.1, 0.1, -1.0);
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f(0.1, -0.1, -1.0);
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(-0.1, -0.1, -1.0);
glEnd();
glPopMatrix();
glPopAttrib();
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
(这里不会发布我的ShaderLoader源代码,因为使用更简单的着色器(切换颜色等)完全可以正常工作)
如果您认为错误出现在其他地方,我很乐意发布一些额外的代码。