| /* Framebuffer object test */ |
| |
| |
| #include <GL/glew.h> |
| #include <GL/glut.h> |
| #include <assert.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <math.h> |
| |
| /* For debug */ |
| |
| |
| static int Win = 0; |
| static int Width = 512, Height = 512; |
| |
| static GLenum TexTarget = GL_TEXTURE_2D; |
| static int TexWidth = 512, TexHeight = 512; |
| |
| static GLuint MyFB; |
| static GLuint TexObj; |
| static GLboolean Anim = GL_FALSE; |
| static GLfloat Rot = 0.0; |
| static GLuint TextureLevel = 0; /* which texture level to render to */ |
| static GLenum TexIntFormat = GL_RGB; /* either GL_RGB or GL_RGBA */ |
| |
| |
| static void |
| CheckError(int line) |
| { |
| GLenum err = glGetError(); |
| if (err) { |
| printf("GL Error 0x%x at line %d\n", (int) err, line); |
| } |
| } |
| |
| |
| static void |
| Idle(void) |
| { |
| Rot = glutGet(GLUT_ELAPSED_TIME) * 0.1; |
| glutPostRedisplay(); |
| } |
| |
| |
| static void |
| RenderTexture(void) |
| { |
| GLenum status; |
| |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0); |
| glMatrixMode(GL_MODELVIEW); |
| glLoadIdentity(); |
| glTranslatef(0.0, 0.0, -15.0); |
| |
| if (1) { |
| /* draw to texture image */ |
| glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB); |
| |
| status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT); |
| if (status != GL_FRAMEBUFFER_COMPLETE_EXT) { |
| printf("Framebuffer incomplete!!!\n"); |
| } |
| |
| glViewport(0, 0, TexWidth, TexHeight); |
| |
| glClearColor(0.5, 0.5, 1.0, 0.0); |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| CheckError(__LINE__); |
| |
| glBegin(GL_POLYGON); |
| glColor3f(1, 0, 0); |
| glVertex2f(-1, -1); |
| glColor3f(0, 1, 0); |
| glVertex2f(1, -1); |
| glColor3f(0, 0, 1); |
| glVertex2f(0, 1); |
| glEnd(); |
| |
| /* Bind normal framebuffer */ |
| glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); |
| } |
| else { |
| } |
| |
| CheckError(__LINE__); |
| } |
| |
| |
| |
| static void |
| Display(void) |
| { |
| float ar = (float) Width / (float) Height; |
| |
| RenderTexture(); |
| |
| /* draw textured quad in the window */ |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0); |
| glMatrixMode(GL_MODELVIEW); |
| glLoadIdentity(); |
| glTranslatef(0.0, 0.0, -7.0); |
| |
| glViewport(0, 0, Width, Height); |
| |
| glClearColor(0.25, 0.25, 0.25, 0); |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| glPushMatrix(); |
| glRotatef(Rot, 0, 1, 0); |
| glEnable(TexTarget); |
| glBindTexture(TexTarget, TexObj); |
| |
| { |
| glBegin(GL_POLYGON); |
| glColor3f(0.25, 0.25, 0.25); |
| glTexCoord2f(0, 0); |
| glVertex2f(-1, -1); |
| glTexCoord2f(1, 0); |
| glVertex2f(1, -1); |
| glColor3f(1.0, 1.0, 1.0); |
| glTexCoord2f(1, 1); |
| glVertex2f(1, 1); |
| glTexCoord2f(0, 1); |
| glVertex2f(-1, 1); |
| glEnd(); |
| } |
| |
| glPopMatrix(); |
| glDisable(TexTarget); |
| |
| glutSwapBuffers(); |
| CheckError(__LINE__); |
| } |
| |
| |
| static void |
| Reshape(int width, int height) |
| { |
| glViewport(0, 0, width, height); |
| Width = width; |
| Height = height; |
| } |
| |
| |
| static void |
| CleanUp(void) |
| { |
| glDeleteFramebuffersEXT(1, &MyFB); |
| |
| glDeleteTextures(1, &TexObj); |
| |
| glutDestroyWindow(Win); |
| |
| exit(0); |
| } |
| |
| |
| static void |
| Key(unsigned char key, int x, int y) |
| { |
| (void) x; |
| (void) y; |
| switch (key) { |
| case 'a': |
| Anim = !Anim; |
| if (Anim) |
| glutIdleFunc(Idle); |
| else |
| glutIdleFunc(NULL); |
| break; |
| case 's': |
| Rot += 2.0; |
| break; |
| case 27: |
| CleanUp(); |
| break; |
| } |
| glutPostRedisplay(); |
| } |
| |
| |
| static void |
| Init(int argc, char *argv[]) |
| { |
| static const GLfloat mat[4] = { 1.0, 0.5, 0.5, 1.0 }; |
| GLint i; |
| |
| if (!glutExtensionSupported("GL_EXT_framebuffer_object")) { |
| printf("GL_EXT_framebuffer_object not found!\n"); |
| exit(0); |
| } |
| |
| printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); |
| |
| |
| /* Make texture object/image */ |
| glGenTextures(1, &TexObj); |
| glBindTexture(TexTarget, TexObj); |
| glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST); |
| glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST); |
| glTexParameteri(TexTarget, GL_TEXTURE_BASE_LEVEL, TextureLevel); |
| glTexParameteri(TexTarget, GL_TEXTURE_MAX_LEVEL, TextureLevel); |
| |
| glTexImage2D(TexTarget, 0, TexIntFormat, TexWidth, TexHeight, 0, |
| GL_RGBA, GL_UNSIGNED_BYTE, NULL); |
| |
| |
| glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); |
| |
| |
| |
| |
| /* gen framebuffer id, delete it, do some assertions, just for testing */ |
| glGenFramebuffersEXT(1, &MyFB); |
| glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB); |
| assert(glIsFramebufferEXT(MyFB)); |
| |
| |
| CheckError(__LINE__); |
| |
| /* Render color to texture */ |
| glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, |
| TexTarget, TexObj, TextureLevel); |
| |
| |
| |
| CheckError(__LINE__); |
| |
| /* bind regular framebuffer */ |
| glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); |
| |
| |
| } |
| |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| glutInit(&argc, argv); |
| glutInitWindowPosition(0, 0); |
| glutInitWindowSize(Width, Height); |
| glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE); |
| Win = glutCreateWindow(argv[0]); |
| glewInit(); |
| glutReshapeFunc(Reshape); |
| glutKeyboardFunc(Key); |
| glutDisplayFunc(Display); |
| if (Anim) |
| glutIdleFunc(Idle); |
| Init(argc, argv); |
| glutMainLoop(); |
| return 0; |
| } |