408 lines
9.8 KiB
C
408 lines
9.8 KiB
C
/*
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* Test GL_EXT_framebuffer_object render-to-texture
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*
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* Draw a teapot into a texture image with stenciling.
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* Then draw a textured quad using that texture.
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*
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* Brian Paul
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* 18 Apr 2005
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*/
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#define GL_GLEXT_PROTOTYPES
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#include <GL/glut.h>
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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/* For debug */
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#define DEPTH 1
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#define STENCIL 1
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#define DRAW 1
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static int Win = 0;
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static int Width = 400, Height = 400;
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static GLenum TexTarget = GL_TEXTURE_2D; /*GL_TEXTURE_RECTANGLE_ARB;*/
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static int TexWidth = 512, TexHeight = 512;
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/*static int TexWidth = 600, TexHeight = 600;*/
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static GLuint MyFB;
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static GLuint TexObj;
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static GLuint DepthRB, StencilRB;
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static GLboolean Anim = GL_FALSE;
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static GLfloat Rot = 0.0;
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static GLboolean UsePackedDepthStencil = GL_FALSE;
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static GLuint TextureLevel = 1; /* which texture level to render to */
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static GLenum TexIntFormat = GL_RGB; /* either GL_RGB or GL_RGBA */
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static void
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CheckError(int line)
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{
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GLenum err = glGetError();
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if (err) {
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printf("GL Error 0x%x at line %d\n", (int) err, line);
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}
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}
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static void
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Idle(void)
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{
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Rot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
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glutPostRedisplay();
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}
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static void
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RenderTexture(void)
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{
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GLenum status;
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef(0.0, 0.0, -15.0);
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/* draw to texture image */
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glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
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status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
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if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
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printf("Framebuffer incomplete!!!\n");
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}
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glViewport(0, 0, TexWidth, TexHeight);
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glClearColor(0.5, 0.5, 1.0, 0.0);
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
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CheckError(__LINE__);
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#if DEPTH
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glEnable(GL_DEPTH_TEST);
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#endif
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#if STENCIL
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glEnable(GL_STENCIL_TEST);
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glStencilFunc(GL_NEVER, 1, ~0);
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glStencilOp(GL_REPLACE, GL_KEEP, GL_REPLACE);
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#endif
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CheckError(__LINE__);
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#if DEPTH || STENCIL
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/* draw diamond-shaped stencil pattern */
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glColor3f(0, 1, 0);
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glBegin(GL_POLYGON);
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glVertex2f(-0.2, 0.0);
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glVertex2f( 0.0, -0.2);
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glVertex2f( 0.2, 0.0);
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glVertex2f( 0.0, 0.2);
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glEnd();
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#endif
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/* draw teapot where stencil != 1 */
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#if STENCIL
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glStencilFunc(GL_NOTEQUAL, 1, ~0);
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glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
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#endif
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CheckError(__LINE__);
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#if 0
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glBegin(GL_POLYGON);
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glColor3f(1, 0, 0);
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glVertex2f(-1, -1);
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glColor3f(0, 1, 0);
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glVertex2f(1, -1);
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glColor3f(0, 0, 1);
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glVertex2f(0, 1);
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glEnd();
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#else
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glPushMatrix();
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glRotatef(0.5 * Rot, 1.0, 0.0, 0.0);
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glutSolidTeapot(0.5);
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glPopMatrix();
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glDisable(GL_LIGHTING);
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/*
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PrintStencilHistogram(TexWidth, TexHeight);
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*/
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#endif
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glDisable(GL_DEPTH_TEST);
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glDisable(GL_STENCIL_TEST);
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#if DRAW
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/* Bind normal framebuffer */
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glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
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#endif
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CheckError(__LINE__);
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}
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static void
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Display(void)
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{
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float ar = (float) Width / (float) Height;
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RenderTexture();
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/* draw textured quad in the window */
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#if DRAW
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef(0.0, 0.0, -7.0);
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glViewport(0, 0, Width, Height);
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glClearColor(0.25, 0.25, 0.25, 0);
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glClear(GL_COLOR_BUFFER_BIT);
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glPushMatrix();
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glRotatef(Rot, 0, 1, 0);
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glEnable(TexTarget);
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glBindTexture(TexTarget, TexObj);
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glBegin(GL_POLYGON);
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glColor3f(0.25, 0.25, 0.25);
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if (TexTarget == GL_TEXTURE_2D) {
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glTexCoord2f(0, 0);
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glVertex2f(-1, -1);
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glTexCoord2f(1, 0);
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glVertex2f(1, -1);
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glColor3f(1.0, 1.0, 1.0);
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glTexCoord2f(1, 1);
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glVertex2f(1, 1);
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glTexCoord2f(0, 1);
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glVertex2f(-1, 1);
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}
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else {
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assert(TexTarget == GL_TEXTURE_RECTANGLE_ARB);
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glTexCoord2f(0, 0);
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glVertex2f(-1, -1);
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glTexCoord2f(TexWidth, 0);
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glVertex2f(1, -1);
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glColor3f(1.0, 1.0, 1.0);
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glTexCoord2f(TexWidth, TexHeight);
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glVertex2f(1, 1);
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glTexCoord2f(0, TexHeight);
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glVertex2f(-1, 1);
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}
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glEnd();
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glPopMatrix();
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glDisable(TexTarget);
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#endif
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glutSwapBuffers();
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CheckError(__LINE__);
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}
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static void
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Reshape(int width, int height)
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{
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glViewport(0, 0, width, height);
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Width = width;
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Height = height;
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}
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static void
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CleanUp(void)
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{
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#if DEPTH
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glDeleteRenderbuffersEXT(1, &DepthRB);
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#endif
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#if STENCIL
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if (!UsePackedDepthStencil)
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glDeleteRenderbuffersEXT(1, &StencilRB);
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#endif
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glDeleteFramebuffersEXT(1, &MyFB);
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glDeleteTextures(1, &TexObj);
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glutDestroyWindow(Win);
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exit(0);
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}
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static void
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Key(unsigned char key, int x, int y)
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{
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(void) x;
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(void) y;
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switch (key) {
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case 'a':
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Anim = !Anim;
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if (Anim)
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glutIdleFunc(Idle);
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else
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glutIdleFunc(NULL);
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break;
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case 's':
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Rot += 2.0;
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break;
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case 27:
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CleanUp();
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break;
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}
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glutPostRedisplay();
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}
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static void
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Init(int argc, char *argv[])
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{
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static const GLfloat mat[4] = { 1.0, 0.5, 0.5, 1.0 };
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GLint i;
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if (!glutExtensionSupported("GL_EXT_framebuffer_object")) {
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printf("GL_EXT_framebuffer_object not found!\n");
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exit(0);
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}
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if (argc > 1 && strcmp(argv[1], "-ds") == 0) {
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if (!glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
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printf("GL_EXT_packed_depth_stencil not found!\n");
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exit(0);
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}
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UsePackedDepthStencil = GL_TRUE;
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printf("Using GL_EXT_packed_depth_stencil\n");
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}
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printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
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/* gen framebuffer id, delete it, do some assertions, just for testing */
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glGenFramebuffersEXT(1, &MyFB);
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assert(MyFB);
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assert(!glIsFramebufferEXT(MyFB));
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glDeleteFramebuffersEXT(1, &MyFB);
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assert(!glIsFramebufferEXT(MyFB));
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/* Note, continue to use MyFB below */
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glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
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assert(glIsFramebufferEXT(MyFB));
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glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
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assert(i == MyFB);
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/* Make texture object/image */
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glGenTextures(1, &TexObj);
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glBindTexture(TexTarget, TexObj);
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/* make two image levels */
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glTexImage2D(TexTarget, 0, TexIntFormat, TexWidth, TexHeight, 0,
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GL_RGBA, GL_UNSIGNED_BYTE, NULL);
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glTexImage2D(TexTarget, 1, TexIntFormat, TexWidth/2, TexHeight/2, 0,
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GL_RGBA, GL_UNSIGNED_BYTE, NULL);
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TexWidth = TexWidth >> TextureLevel;
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TexHeight = TexHeight >> TextureLevel;
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glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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glTexParameteri(TexTarget, GL_TEXTURE_BASE_LEVEL, TextureLevel);
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glTexParameteri(TexTarget, GL_TEXTURE_MAX_LEVEL, TextureLevel);
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CheckError(__LINE__);
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/* Render color to texture */
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glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
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TexTarget, TexObj, TextureLevel);
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#if DEPTH
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/* make depth renderbuffer */
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glGenRenderbuffersEXT(1, &DepthRB);
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assert(DepthRB);
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assert(!glIsRenderbufferEXT(DepthRB));
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glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, DepthRB);
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assert(glIsRenderbufferEXT(DepthRB));
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if (UsePackedDepthStencil)
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glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_STENCIL_EXT,
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TexWidth, TexHeight);
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else
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glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT,
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TexWidth, TexHeight);
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CheckError(__LINE__);
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glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
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GL_RENDERBUFFER_DEPTH_SIZE_EXT, &i);
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CheckError(__LINE__);
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printf("Depth renderbuffer size = %d bits\n", i);
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assert(i > 0);
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/* attach DepthRB to MyFB */
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glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
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GL_RENDERBUFFER_EXT, DepthRB);
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#endif
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CheckError(__LINE__);
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#if STENCIL
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if (UsePackedDepthStencil) {
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/* DepthRb is a combined depth/stencil renderbuffer */
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glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
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GL_STENCIL_ATTACHMENT_EXT,
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GL_RENDERBUFFER_EXT, DepthRB);
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}
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else {
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/* make stencil renderbuffer */
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glGenRenderbuffersEXT(1, &StencilRB);
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assert(StencilRB);
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assert(!glIsRenderbufferEXT(StencilRB));
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glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, StencilRB);
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assert(glIsRenderbufferEXT(StencilRB));
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glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX,
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TexWidth, TexHeight);
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/* attach StencilRB to MyFB */
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glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
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GL_STENCIL_ATTACHMENT_EXT,
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GL_RENDERBUFFER_EXT, StencilRB);
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}
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glGetRenderbufferParameterivEXT(GL_RENDERBUFFER_EXT,
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GL_RENDERBUFFER_STENCIL_SIZE_EXT, &i);
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CheckError(__LINE__);
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printf("Stencil renderbuffer size = %d bits\n", i);
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assert(i > 0);
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#endif
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CheckError(__LINE__);
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/* bind regular framebuffer */
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glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
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/* lighting */
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glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat);
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}
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int
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main(int argc, char *argv[])
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{
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glutInit(&argc, argv);
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glutInitWindowPosition(0, 0);
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glutInitWindowSize(Width, Height);
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glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
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Win = glutCreateWindow(argv[0]);
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glutReshapeFunc(Reshape);
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glutKeyboardFunc(Key);
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glutDisplayFunc(Display);
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if (Anim)
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glutIdleFunc(Idle);
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Init(argc, argv);
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glutMainLoop();
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return 0;
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}
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