#include <string.h>
#include <math.h>
+/* For debug */
+#define DEPTH 1
+#define STENCIL 1
+#define DRAW 1
+
static int Width = 400, Height = 400;
+
+static GLenum TexTarget = GL_TEXTURE_2D; /*GL_TEXTURE_RECTANGLE_ARB;*/
static int TexWidth = 512, TexHeight = 512;
+/*static int TexWidth = 600, TexHeight = 600;*/
+
static GLuint MyFB;
static GLuint TexObj;
static GLuint DepthRB, StencilRB;
static GLboolean Anim = GL_FALSE;
static GLfloat Rot = 0.0;
static GLboolean UsePackedDepthStencil = GL_FALSE;
+static GLuint TextureLevel = 1; /* which texture level to render to */
+static GLenum TexIntFormat = GL_RGB; /* either GL_RGB or GL_RGBA */
static void
static void
Idle(void)
{
- Rot = glutGet(GLUT_ELAPSED_TIME) * 0.05;
+ Rot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
glutPostRedisplay();
}
static void
RenderTexture(void)
{
- GLint level = 0;
GLenum status;
glMatrixMode(GL_PROJECTION);
glTranslatef(0.0, 0.0, -15.0);
/* draw to texture image */
- glBindTexture(GL_TEXTURE_2D, 0);
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) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
CheckError(__LINE__);
+#if DEPTH
glEnable(GL_DEPTH_TEST);
+#endif
+
+#if STENCIL
glEnable(GL_STENCIL_TEST);
glStencilFunc(GL_NEVER, 1, ~0);
glStencilOp(GL_REPLACE, GL_KEEP, GL_REPLACE);
+#endif
CheckError(__LINE__);
+#if DEPTH || STENCIL
/* draw diamond-shaped stencil pattern */
glColor3f(0, 1, 0);
glBegin(GL_POLYGON);
glVertex2f( 0.2, 0.0);
glVertex2f( 0.0, 0.2);
glEnd();
+#endif
/* draw teapot where stencil != 1 */
+#if STENCIL
glStencilFunc(GL_NOTEQUAL, 1, ~0);
glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
+#endif
CheckError(__LINE__);
glutSolidTeapot(0.5);
glPopMatrix();
glDisable(GL_LIGHTING);
+ /*
+ PrintStencilHistogram(TexWidth, TexHeight);
+ */
#endif
+
glDisable(GL_DEPTH_TEST);
glDisable(GL_STENCIL_TEST);
+#if DRAW
/* Bind normal framebuffer */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+#endif
CheckError(__LINE__);
}
RenderTexture();
/* draw textured quad in the window */
-
+#if DRAW
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-ar, ar, -1.0, 1.0, 5.0, 25.0);
glPushMatrix();
glRotatef(Rot, 0, 1, 0);
- glEnable(GL_TEXTURE_2D);
- glBindTexture(GL_TEXTURE_2D, TexObj);
+ 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);
+ if (TexTarget == GL_TEXTURE_2D) {
+ 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);
+ }
+ else {
+ assert(TexTarget == GL_TEXTURE_RECTANGLE_ARB);
+ glTexCoord2f(0, 0);
+ glVertex2f(-1, -1);
+ glTexCoord2f(TexWidth, 0);
+ glVertex2f(1, -1);
+ glColor3f(1.0, 1.0, 1.0);
+ glTexCoord2f(TexWidth, TexHeight);
+ glVertex2f(1, 1);
+ glTexCoord2f(0, TexHeight);
+ glVertex2f(-1, 1);
+ }
glEnd();
glPopMatrix();
- glDisable(GL_TEXTURE_2D);
-
+ glDisable(TexTarget);
+#endif
+
glutSwapBuffers();
CheckError(__LINE__);
}
static void
CleanUp(void)
{
+#if DEPTH
glDeleteRenderbuffersEXT(1, &DepthRB);
+#endif
+#if STENCIL
if (!UsePackedDepthStencil)
glDeleteRenderbuffersEXT(1, &StencilRB);
+#endif
glDeleteFramebuffersEXT(1, &MyFB);
glDeleteTextures(1, &TexObj);
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")) {
glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &i);
assert(i == MyFB);
+ /* Make texture object/image */
+ glGenTextures(1, &TexObj);
+ glBindTexture(TexTarget, TexObj);
+ /* make two image levels */
+ glTexImage2D(TexTarget, 0, TexIntFormat, TexWidth, TexHeight, 0,
+ GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+ glTexImage2D(TexTarget, 1, TexIntFormat, TexWidth/2, TexHeight/2, 0,
+ GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+ TexWidth = TexWidth >> TextureLevel;
+ TexHeight = TexHeight >> TextureLevel;
+
+ glTexParameteri(TexTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+ glTexParameteri(TexTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+ glTexParameteri(TexTarget, GL_TEXTURE_BASE_LEVEL, TextureLevel);
+ glTexParameteri(TexTarget, GL_TEXTURE_MAX_LEVEL, TextureLevel);
+
+ CheckError(__LINE__);
+
+ /* Render color to texture */
+ glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+ TexTarget, TexObj, TextureLevel);
+
+
+#if DEPTH
/* make depth renderbuffer */
glGenRenderbuffersEXT(1, &DepthRB);
assert(DepthRB);
/* attach DepthRB to MyFB */
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
GL_RENDERBUFFER_EXT, DepthRB);
+#endif
CheckError(__LINE__);
+#if STENCIL
if (UsePackedDepthStencil) {
/* DepthRb is a combined depth/stencil renderbuffer */
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
CheckError(__LINE__);
printf("Stencil renderbuffer size = %d bits\n", i);
assert(i > 0);
+#endif
+ CheckError(__LINE__);
/* bind regular framebuffer */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
- CheckError(__LINE__);
-
- /* 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__);
+ /* lighting */
+ glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat);
}