這是相當複雜的,如果你是着色器和FBO的新手,它將需要一些時間來理解它。所以這裏有一些最小的未經測試的OpenGL代碼,它們實現了Danvil's answer。錯誤檢查已被排除在外;它很複雜,因爲它是。如果你多次調用這個函數,你應該保持在這個代碼中創建的任何或所有對象。
如果你不關心速度,VilleK's answer的CPU上運行是一個容易得多...
// Create the target texture object.
GLuint target;
glGenTextures(1, &target);
// Bind the target texture.
glBindTexture(GL_TEXTURE_2D, target);
// Allocate texture memory. width and height must be the size of the original texture.
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
// Create a framebuffer object.
GLuint fbo;
glGenFramebuffers(1, &fbo);
// Bind the framebuffer object.
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
// Attach the target texture as the render target.
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, target, 0);
// Check framebuffer status.
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
throw "Framebuffer incomplete.";
// Create fragment shader to do the transformation.
GLuint frag = glCreateShader(GL_FRAGMENT_SHADER);
// Set the shader's source code.
char const *source =
"uniform sampler2D input;\n"
"uniform float hShift, sMult, lMult;\n"
"void main() {\n"
" vec4 color = texture2D(input, gl_FragCoord.xy);\n"
" /* Do your HSL transformations here... */\n"
" gl_FragColor = color;\n"
"}\n";
glShaderSource(frag, 1, &source, 0);
// Compile the shader.
glCompileShader(frag);
// Check compilation result. Here, you probably want to use glGetShaderInfoLog() to get any compilation errors.
GLint status;
glGetShader(frag, GL_COMPILE_STATUS, &status);
if (status == GL_FALSE)
throw "Shader compilation failed";
// Create the program.
GLuint program = glCreateProgram();
// Attach the shader to the program.
glAttachShader(program, frag);
// Link the program.
glLinkProgram(program);
// Check link result. Here, you probably want to use glGetProgramInfoLog() to get any link errors.
glGetProgram(program, GL_LINK_STATUS, &status);
if (status == GL_FALSE)
throw "Program linking failed"
// Use the program for subsequent rendering.
glUseProgram(program);
// Set the values of the uniform parameters.
glUniform1i(glUniformLocation(program, "input"), 0);
glUniform1f(glUniformLocation(program, "hShift"), hShift);
glUniform1f(glUniformLocation(program, "sMult"), sMult);
glUniform1f(glUniformLocation(program, "lMult"), lMult);
// Bind the source texture to read from.
glBindTexture(GL_TEXTURE_2D, texture);
// Set up the viewport and matrices.
glPushAttrib(GL_VIEWPORT_BIT | GL_TRANSFORM_BIT);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0, 1, 0, 1, 0, 1);
glViewport(0, 0, width, height);
// Render a quad.
glBegin(GL_QUADS);
glVertex2i(0, 0);
glVertex2i(1, 0);
glVertex2i(1, 1);
glVertex2i(0, 1);
glEnd();
// Restore the matrices and viewport.
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glPopAttrib();
// Stop using the program.
glUseProgram(0);
// Stop using the framebuffer object.
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// Delete created objects.
glDeleteProgram(program);
glDeleteShader(frag);
glDeleteFramebuffers(1, &fbo);
// Optionally, delete the old, untransformed texture.
glDeleteTextures(1, &texture);
// Return the new texture.
return target;
希望有所幫助。對於2.0之前的OpenGL,您需要首先加載合適的擴展,然後在一些EXT
s和/或ARB
s處打耳光。
如果你願意順着這條道路走下去,不要猶豫,隨時發表評論來描述你遇到的問題。我很樂意提供幫助!
哇!你在那裏做了一些不錯的工作:)我懶得寫出來;) – Danvil 2010-04-30 15:24:31