3
我想实现一个简单的程序,使用3 FBO的渲染场景到纹理和显示纹理四。在投影到纹理四元组之前,我已经成功使用片段着色器完成此操作,但无法在没有着色器的情况下使用片段着色器。什么可能是错的?
首先,我建立了我的纹理为什么我无法使用FBO正确渲染对象?
glGenTextures(3, renderTextureID);
for (GLint i = 0; i < 3; i++)
{
glBindTexture(GL_TEXTURE_2D, renderTextureID[i]);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// this may change with window size changes
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, fboWidth, fboHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
}
下一页一些帧缓冲状态
glGenFramebuffersEXT(3, framebufferID);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[0]);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, renderTextureID[0], 0);
GLenum fboStatus = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
if(fboStatus != GL_FRAMEBUFFER_COMPLETE_EXT)
{
fprintf(stderr, "FBO Error!");
}
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[1]);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, renderTextureID[1], 0);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[2]);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, renderTextureID[2], 0);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
然后我渲染场景
glViewport(0, 0, fboWidth, fboHeight);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebufferID[0]);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
drawModels();
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
ADDED: glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, renderTextureID[0]);
glEnable(GL_SCISSOR_TEST);
glViewport(windowWidth/2, 0, fboWidth, fboHeight);
glScissor(windowWidth/2, 0, fboWidth, fboHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glBegin(GL_QUADS);
glTexCoord2i(0, 0);
glVertex2f(-1.0f, -1.0f);
glTexCoord2i(1, 0);
glVertex2f(1.0f, -1.0f);
glTexCoord2i(1, 1);
glVertex2f(1.0f, 1.0f);
glTexCoord2i(0, 1);
glVertex2f(-1.0f, 1.0f);
glEnd();
glDisable(GL_SCISSOR_TEST);
ADDED: glDisable(GL_TEXTURE_2D);
glutSwapBuffers();
结果是一个黄色的方形。如果不使用FBO,绘制模型绘制黄色线框立方体,所以问题不是这样。我读过一篇前面类似的文章,讲述了在生成和绑定纹理之后使用glTexParameterf,但我已经完成了这个。
谢谢...
Theres no GL error。如果我在使用glUseProgram之前使用glUseProgram,然后输出很好,但是如果我在调用glUseProgram(0)之后尝试使用纹理,我再次得到黄色方块 – Brett 2010-03-25 19:01:26
@Brett:那么这是固定函数的问题建立。我在我的答案中增加了另一个猜测。 – Bahbar 2010-03-25 20:06:24
好的。所以我想我明白了。我在上面的代码中添加了一个glEnable(GL_TEXTURE_2D),现在它可以工作,谢谢Bahbar。 – Brett 2010-03-26 10:53:00