/* * Test GL_EXT_framebuffer_object render-to-texture * * Draw a teapot into a texture image with stenciling. * Then draw a textured quad using that texture. * * Brian Paul * 18 Apr 2005 */ #define GL_GLEXT_PROTOTYPES #include #include #include #include #include static int Width = 400, Height = 400; static int TexWidth = 512, TexHeight = 512; static GLuint MyFB; static GLuint TexObj; static GLuint DepthRB, StencilRB; static GLboolean Anim = GL_FALSE; static GLfloat Rot = 0.0; 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) * 0.05; glutPostRedisplay(); } static void RenderTexture(void) { GLint level = 0; 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); /* draw to texture */ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB); glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, TexObj, level); 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 | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); glEnable(GL_DEPTH_TEST); glEnable(GL_STENCIL_TEST); glStencilFunc(GL_NEVER, 1, ~0); glStencilOp(GL_REPLACE, GL_KEEP, GL_REPLACE); /* draw diamond-shaped stencil pattern */ glColor3f(0, 1, 0); glBegin(GL_POLYGON); glVertex2f(-0.2, 0.0); glVertex2f( 0.0, -0.2); glVertex2f( 0.2, 0.0); glVertex2f( 0.0, 0.2); glEnd(); /* draw teapot where stencil != 1 */ glStencilFunc(GL_NOTEQUAL, 1, ~0); glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP); #if 0 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(); #else glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glPushMatrix(); glRotatef(0.5 * Rot, 1.0, 0.0, 0.0); glutSolidTeapot(0.5); glPopMatrix(); glDisable(GL_LIGHTING); #endif glDisable(GL_DEPTH_TEST); glDisable(GL_STENCIL_TEST); /* Bind normal framebuffer */ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); 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(GL_TEXTURE_2D); 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(GL_TEXTURE_2D); glutSwapBuffers(); CheckError(__LINE__); } static void Reshape(int width, int height) { glViewport(0, 0, width, height); Width = width; Height = height; } 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 27: exit(0); break; } glutPostRedisplay(); } static void Init(void) { 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 framebuffer */ glGenFramebuffersEXT(1, &MyFB); assert(MyFB); assert(!glIsFramebufferEXT(MyFB)); glDeleteFramebuffersEXT(1, &MyFB); assert(!glIsFramebufferEXT(MyFB)); /* Note, continue to use MyFB below */ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB); assert(glIsFramebufferEXT(MyFB)); glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i); assert(i == MyFB); /* make depth renderbuffer */ glGenRenderbuffersEXT(1, &DepthRB); assert(DepthRB); assert(!glIsRenderbufferEXT(DepthRB)); glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthRB); glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, TexWidth, TexHeight); glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT, GL_RENDERBUFFER_DEPTH_SIZE_EXT, &i); printf("Depth renderbuffer size = %d bits\n", i); assert(i > 0); /* make stencil renderbuffer */ glGenRenderbuffersEXT(1, &StencilRB); assert(StencilRB); assert(!glIsRenderbufferEXT(StencilRB)); glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, StencilRB); glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, TexWidth, TexHeight); glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT, GL_RENDERBUFFER_STENCIL_SIZE_EXT, &i); printf("Stencil renderbuffer size = %d bits\n", i); assert(i > 0); /* attach DepthRB to MyFB */ glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, DepthRB); /* attach StencilRB to MyFB */ glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, StencilRB); /* bind regular framebuffer */ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); /* Make texture object/image */ glGenTextures(1, &TexObj); glBindTexture(GL_TEXTURE_2D, TexObj); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, TexWidth, TexHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); CheckError(__LINE__); } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitWindowPosition(0, 0); glutInitWindowSize(Width, Height); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE); glutCreateWindow(argv[0]); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutDisplayFunc(Display); if (Anim) glutIdleFunc(Idle); Init(); glutMainLoop(); return 0; }