3
我想實現一個簡單的程序,使用3 FBO的渲染場景到紋理和顯示紋理四。在投影到紋理四元組之前,我已經成功使用片段着色器完成此操作,但無法在沒有着色器的情況下使用片段着色器。什麼可能是錯的?
首先,我建立了我的紋理爲什麼我無法使用FBO正確渲染對象?
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);
}
下一頁一些幀緩衝狀態
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);
然後我渲染場景
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();
結果是一個黃色的方形。如果不使用FBO,繪製模型繪製黃色線框立方體,所以問題不是這樣。我讀過一篇前面類似的文章,講述了在生成和綁定紋理之後使用glTexParameterf,但我已經完成了這個。
謝謝...
Theres no GL error。如果我在使用glUseProgram之前使用glUseProgram,然後輸出很好,但是如果我在調用glUseProgram(0)之後嘗試使用紋理,我再次得到黃色方塊 – Brett 2010-03-25 19:01:26
@Brett:那麼這是固定函數的問題建立。我在我的答案中增加了另一個猜測。 – Bahbar 2010-03-25 20:06:24
好的。所以我想我明白了。我在上面的代碼中添加了一個glEnable(GL_TEXTURE_2D),現在它可以工作,謝謝Bahbar。 – Brett 2010-03-26 10:53:00