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我目前正試圖在OpenGL圖像處理算法中實現。用於過濾器的GPU-成色着色器上的圖像處理 - FBO
我想先後使用幾個着色器來執行幾個過濾器（Sobel Gaussian，...）。 我明白，要做到這一點，我不得不渲染紋理感謝FBO。我讀了很多關於這方面的知識，並編寫了一個代碼。但是我沒有得到我期望的結果。
目前，我只是想使用兩個着色器。所以，我有一個原始圖像，這是我的第一個着色器的輸入。然後，我想將着色器的輸出渲染爲紋理，然後紋理將成爲我的第二個着色器（乒乓技術）的輸入。最後，我想顯示第二個着色器的輸出。
但因此，我得到的原始圖像。
我的代碼如下：
/******************** Shaders Function *******************************/
void setupShaders(char *vert, char *frag, GLuint p) {
GLuint v, f;
char *vs = NULL,*fs = NULL;
v = glCreateShader(GL_VERTEX_SHADER);
f = glCreateShader(GL_FRAGMENT_SHADER);
vs = textFileRead(vert);
fs = textFileRead(frag);
const char * ff = fs;
const char * vv = vs;
glShaderSource(v, 1, &vv, NULL);
glShaderSource(f, 1, &ff, NULL);
free(vs);free(fs);
glCompileShader(v);
glCompileShader(f);
p = glCreateProgram();
glAttachShader(p,f);
glAttachShader(p,v);
glLinkProgram(p);
glUseProgram(p);
}
/******************** Texture Function ***********************************/
void setupTexture(void) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
}
/******************** Quad Drawing Function ******************************/
void ShaderDraw(void){
glBegin(GL_QUADS);
glTexCoord2f(0.0, 0.0); glVertex3f(0.0, 0.0, 0.0);
glTexCoord2f(0.0, 1.0); glVertex3f(0.0, height, 0.0);
glTexCoord2f(1.0, 1.0); glVertex3f(width, height, 0.0);
glTexCoord2f(1.0, 0.0); glVertex3f(width, height, 0.0);
glEnd();
}
/******************** Initialization Function ***************************/
void init(void)
{
//Checking GLSL
glewInit();
if (glewIsSupported("GL_VERSION_2_0"))
printf("Ready for OpenGL 2.0\n");
else {
printf("OpenGL 2.0 not supported\n");
exit(1);
}
// Init
glClearColor (0.0, 0.0, 0.0, 0.0);
glShadeModel(GL_FLAT);
glEnable(GL_DEPTH_TEST);
}
/******************** Display Function **********************************/
void display(void)
{
glEnable(GL_TEXTURE_2D);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
glBegin(GL_QUADS);
glTexCoord2f(0.0, 0.0); glVertex3f(-4.0, -4.0, 0.0);
glTexCoord2f(0.0, 1.0); glVertex3f(-4.0, 4.0, 0.0);
glTexCoord2f(1.0, 1.0); glVertex3f(4.0, 4.0, 0.0);
glTexCoord2f(1.0, 0.0); glVertex3f(4.0, -4.0, 0.0);
glEnd();
glFlush();
glDisable(GL_TEXTURE_2D);
}
/******************** Reshape Function *********************************/
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 100.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -7.0);
}
/******************** Main Function *************************************/
int main(int argc, char** argv)
{
// Glut Initialisation
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
// Window Generation
glutInitWindowSize(1000,800);
glutInitWindowPosition(100, 100);
glutCreateWindow("Night Vision");
// Initialisation Function
init();
// Downloading Image
data = cLoadBitmap("lena.bmp", &height, &width);
checkGLErrors ("Downloading Image");
int read_tex = 0;
int write_tex = 1;
// Generating Texture
glEnable(GL_TEXTURE_2D);
glGenTextures(2, texImg);
// Init Texture0
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texImg[read_tex]);
setupTexture();
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
checkGLErrors ("InitTexture0");
// Init Texture1
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texImg[write_tex]);
setupTexture();
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
checkGLErrors ("InitTexture1");
// Setup Framebuffer Object
GLuint fb;
glGenFramebuffersEXT(1, &fb);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
checkGLErrors ("Framebuffer->fb");
GLenum att_point[] = {GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT};
glBindTexture(GL_TEXTURE_2D, texImg[read_tex]);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, att_point[read_tex], GL_TEXTURE_2D, texImg[read_tex], 0);
glBindTexture(GL_TEXTURE_2D, texImg[write_tex]);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, att_point[write_tex], GL_TEXTURE_2D, texImg[write_tex], 0);
checkFramebufferStatus();
//set the write texture as output buffer for the shader
glDrawBuffer(att_point[write_tex]);
// create, init and enable the shader
setupShaders("filter.vert", "sobel_filter_3.frag", p1);
checkGLErrors ("Shaders 1");
// attach the input texture(read texture) to the first texture unit
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D,texImg[read_tex]);
GLuint texLoc;
texLoc = glGetUniformLocation(p1,"tex");
glUniform1i(texLoc, 0);
// draw a square with the texture on it so to perform the computation
ShaderDraw();
// swap the buffers
read_tex = 1;
write_tex = 0;
// Delete program 1
glDeleteProgram(p1);
// set the write texture as output buffer for the shader
glDrawBuffer(att_point[write_tex]);
// create, init and enable the shaders
setupShaders("filter.vert", "gaussian7.frag", p2);
checkGLErrors ("Shaders 2");
// attach the input texture(read texture) to the first texture unit
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D,texImg[read_tex]);
texLoc = glGetUniformLocation(p2,"tex");
glUniform1i(texLoc, 0);
// draw a square with the texture on it so to perform the computation
ShaderDraw();
// Delete program 2 & disable the FBO
glDeleteProgram(p2);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glUseProgram(0);
// Bind the texture to display
glBindTexture(GL_TEXTURE_2D,texImg[0]);
// Glut Functions: Display, Reshape, Keyboard
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
// Calling Main
glutMainLoop();
return 0;
}
是否有人有什麼是錯的想法???
嗨zenna 我是openframeworks用戶，我試圖實現與你真正一樣的東西。一個簡單的乒乓着色器鏈接在fbo內。 你解決了這個問題嗎？你能指出我的解決方案嗎？ 你能寫在埃洛伊電子郵件{}在telenoika [點]網，請... 我不知道如何使一個PM到您的文章... 非常感謝！ – 2011-02-22 18:57:48
你聽說過OpenCL和CUDA嗎？我認爲這是以可維護的方式執行這些操作的最先進的技術 – fabrizioM 2011-09-08 21:17:21