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Added render to depth texture support with GL_EXT_framebuffer_object. 

Only render the shadow/depth texture when really needed, not every frame.
Remove support for old SGIX shadow extensions.
This commit is contained in:
Brian Paul 2006-04-06 04:11:28 +00:00
parent 5722338ea5
commit 762c3618f5
1 changed files with 227 additions and 99 deletions
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326
progs/demos/shadowtex.c
View File

@ -1,13 +1,16 @@
/*
* Shadow demo using the GL_ARB_depth_texture, GL_ARB_shadow and
* GL_ARB_shadow_ambient extensions (or the old SGIX extensions).
* GL_ARB_shadow_ambient extensions.
*
* Brian Paul
* 19 Feb 2001
*
* Added GL_EXT_shadow_funcs support on 23 March 2002
* Added GL_EXT_packed_depth_stencil support on 15 March 2006.
* Added GL_EXT_framebuffer_object support on 27 March 2006.
* Removed old SGIX extension support on 5 April 2006.
*
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
@ -27,7 +30,7 @@
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#define GL_GLEXT_PROTOTYPES
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
@ -35,12 +38,6 @@
#include <GL/glut.h>
#include "showbuffer.h"
#if 0 /* change to 1 if you want to use the old SGIX extensions */
#undef GL_ARB_depth_texture
#undef GL_ARB_shadow
#undef GL_ARB_shadow_ambient
#endif
#define DEG_TO_RAD (3.14159 / 180.0)
static GLint WindowWidth = 450, WindowHeight = 300;
@ -64,10 +61,19 @@ static GLboolean LinearFilter = GL_FALSE;
static GLfloat Bias = -0.06;
static GLboolean Anim = GL_TRUE;
static GLboolean Anim = GL_FALSE;
static GLboolean NeedNewShadowMap = GL_FALSE;
static GLuint ShadowTexture, GrayTexture;
static GLuint ShadowFBO;
static GLboolean HaveFBO = GL_FALSE;
static GLboolean UseFBO = GL_FALSE;
static GLboolean HavePackedDepthStencil = GL_FALSE;
static GLboolean UsePackedDepthStencil = GL_FALSE;
static GLboolean HaveEXTshadowFuncs = GL_FALSE;
static GLboolean HaveShadowAmbient = GL_FALSE;
static GLint Operator = 0;
static const GLenum OperatorFunc[8] = {
GL_LEQUAL, GL_LESS, GL_GEQUAL, GL_GREATER,
@ -78,7 +84,7 @@ static const char *OperatorName[8] = {
static GLuint DisplayMode;
#define SHOW_NORMAL 0
#define SHOW_SHADOWS 0
#define SHOW_DEPTH_IMAGE 1
#define SHOW_DEPTH_MAPPING 2
#define SHOW_DISTANCE 3
@ -89,6 +95,7 @@ static void
DrawScene(void)
{
GLfloat k = 6;
/* sphere */
glPushMatrix();
glTranslatef(1.6, 2.2, 2.7);
@ -200,9 +207,9 @@ EnableDistanceTexgen(const GLfloat lightPos[4], const GLfloat lightDir[3],
/* nearPoint = point on light direction vector which intersects the
* near plane of the light frustum.
*/
nearPoint[0] = LightPos[0] + lightDir[0] / m * lightNear;
nearPoint[1] = LightPos[1] + lightDir[1] / m * lightNear;
nearPoint[2] = LightPos[2] + lightDir[2] / m * lightNear;
nearPoint[0] = lightPos[0] + lightDir[0] / m * lightNear;
nearPoint[1] = lightPos[1] + lightDir[1] / m * lightNear;
nearPoint[2] = lightPos[2] + lightDir[2] / m * lightNear;
sPlane[0] = lightDir[0] / d / m;
sPlane[1] = lightDir[1] / d / m;
@ -242,20 +249,43 @@ ComputeLightPos(GLfloat dist, GLfloat latitude, GLfloat longitude,
}
/**
* Render the shadow map / depth texture.
* The result will be in the texture object named ShadowTexture.
*/
static void
Display(void)
RenderShadowMap(void)
{
GLfloat ar = (GLfloat) WindowWidth / (GLfloat) WindowHeight;
GLfloat d;
GLenum error;
GLenum depthFormat; /* GL_DEPTH_COMPONENT or GL_DEPTH_STENCIL_EXT */
GLenum depthType; /* GL_UNSIGNED_INT_24_8_EXT or GL_UNSIGNED_INT */
float d;
if (WindowWidth >= 1024 && WindowHeight >= 1024) {
ShadowTexWidth = ShadowTexHeight = 1024;
}
else if (WindowWidth >= 512 && WindowHeight >= 512) {
ShadowTexWidth = ShadowTexHeight = 512;
}
else if (WindowWidth >= 256 && WindowHeight >= 256) {
ShadowTexWidth = ShadowTexHeight = 256;
}
else {
ShadowTexWidth = ShadowTexHeight = 128;
}
printf("Rendering %d x %d depth texture\n", ShadowTexWidth, ShadowTexHeight);
if (UsePackedDepthStencil) {
depthFormat = GL_DEPTH_STENCIL_EXT;
depthType = GL_UNSIGNED_INT_24_8_EXT;
}
else {
depthFormat = GL_DEPTH_COMPONENT;
depthType = GL_UNSIGNED_INT;
}
ComputeLightPos(LightDist, LightLatitude, LightLongitude,
LightPos, SpotDir);
/*
* Step 1: render scene from point of view of the light source
*/
/* compute frustum to enclose spot light cone */
d = ShadowNear * tan(SpotAngle);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-d, d, -d, d, ShadowNear, ShadowFar);
@ -265,73 +295,145 @@ Display(void)
0, 0, 0, /* target */
0, 1, 0); /* up */
if (UseFBO) {
glTexImage2D(GL_TEXTURE_2D, 0, depthFormat,
ShadowTexWidth, ShadowTexHeight, 0,
depthFormat, depthType, NULL);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, ShadowFBO);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
assert(glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT)
== GL_FRAMEBUFFER_COMPLETE_EXT);
}
assert(!glIsEnabled(GL_TEXTURE_1D));
assert(!glIsEnabled(GL_TEXTURE_2D));
glViewport(0, 0, ShadowTexWidth, ShadowTexHeight);
glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
glClear(GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
DrawScene();
/*
* Step 2: copy depth buffer into texture map
*/
if (DisplayMode == SHOW_DEPTH_MAPPING) {
/* load depth image as gray-scale luminance texture */
if (UsePackedDepthStencil) {
GLuint *depth = (GLuint *) malloc(ShadowTexWidth * ShadowTexHeight
* sizeof(GLuint));
if (UseFBO) {
/* all done! */
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
}
else {
/*
* copy depth buffer into the texture map
*/
if (DisplayMode == SHOW_DEPTH_MAPPING) {
/* load depth image as gray-scale luminance texture */
GLuint *depth = (GLuint *)
malloc(ShadowTexWidth * ShadowTexHeight * sizeof(GLuint));
assert(depth);
glReadPixels(0, 0, ShadowTexWidth, ShadowTexHeight,
GL_DEPTH_STENCIL_EXT, GL_UNSIGNED_INT_24_8_EXT, depth);
depthFormat, depthType, depth);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE,
ShadowTexWidth, ShadowTexHeight, 0,
GL_LUMINANCE, GL_UNSIGNED_INT, depth);
free(depth);
}
else {
GLfloat *depth = (GLfloat *) malloc(ShadowTexWidth * ShadowTexHeight
* sizeof(GLfloat));
assert(depth);
glReadPixels(0, 0, ShadowTexWidth, ShadowTexHeight,
GL_DEPTH_COMPONENT, GL_FLOAT, depth);
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE,
ShadowTexWidth, ShadowTexHeight, 0,
GL_LUMINANCE, GL_FLOAT, depth);
free(depth);
/* The normal shadow case - a real depth texture */
glCopyTexImage2D(GL_TEXTURE_2D, 0, depthFormat,
0, 0, ShadowTexWidth, ShadowTexHeight, 0);
if (UsePackedDepthStencil) {
/* debug check */
GLint intFormat;
glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
GL_TEXTURE_INTERNAL_FORMAT, &intFormat);
assert(intFormat == GL_DEPTH_STENCIL_EXT);
}
}
}
else {
/* The normal shadow case */
if (UsePackedDepthStencil) {
GLint intFormat;
glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_STENCIL_EXT,
0, 0, ShadowTexWidth, ShadowTexHeight, 0);
glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
GL_TEXTURE_INTERNAL_FORMAT, &intFormat);
assert(intFormat == GL_DEPTH_STENCIL_EXT);
}
else {
glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
0, 0, ShadowTexWidth, ShadowTexHeight, 0);
}
}
/**
* Show the shadow map as a grayscale image.
*/
static void
ShowShadowMap(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, WindowWidth, 0, WindowHeight, -1, 1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glEnable(GL_TEXTURE_2D);
DisableTexgen();
/* interpret texture's depth values as luminance values */
#if defined(GL_ARB_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE_ARB, GL_LUMINANCE);
#endif
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glBegin(GL_POLYGON);
glTexCoord2f(0, 0); glVertex2f(0, 0);
glTexCoord2f(1, 0); glVertex2f(ShadowTexWidth, 0);
glTexCoord2f(1, 1); glVertex2f(ShadowTexWidth, ShadowTexHeight);
glTexCoord2f(0, 1); glVertex2f(0, ShadowTexHeight);
glEnd();
glDisable(GL_TEXTURE_2D);
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
}
/**
* Redraw window image
*/
static void
Display(void)
{
GLenum error;
ComputeLightPos(LightDist, LightLatitude, LightLongitude,
LightPos, SpotDir);
if (NeedNewShadowMap) {
RenderShadowMap();
NeedNewShadowMap = GL_FALSE;
}
/*
* Step 3: render scene from point of view of the camera
*/
glViewport(0, 0, WindowWidth, WindowHeight);
if (DisplayMode == SHOW_DEPTH_IMAGE) {
ShowDepthBuffer(WindowWidth, WindowHeight, 0, 1);
ShowShadowMap();
}
else {
/* prepare to draw scene from camera's view */
const GLfloat ar = (GLfloat) WindowWidth / (GLfloat) WindowHeight;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-ar, ar, -1.0, 1.0, 4.0, 50.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -22.0);
glRotatef(Xrot, 1, 0, 0);
glRotatef(Yrot, 0, 1, 0);
glRotatef(Zrot, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLightfv(GL_LIGHT0, GL_POSITION, LightPos);
if (LinearFilter) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
@ -340,11 +442,10 @@ Display(void)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}
if (DisplayMode == SHOW_DEPTH_MAPPING) {
#if defined(GL_ARB_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
#elif defined(GL_SGIX_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_SGIX, GL_FALSE);
#endif
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
@ -358,21 +459,22 @@ Display(void)
EnableDistanceTexgen(LightPos, SpotDir, ShadowNear+Bias, ShadowFar);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_1D);
assert(!glIsEnabled(GL_TEXTURE_2D));
}
else {
assert(DisplayMode == SHOW_NORMAL);
assert(DisplayMode == SHOW_SHADOWS);
#if defined(GL_ARB_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
GL_COMPARE_R_TO_TEXTURE_ARB);
#elif defined(GL_SGIX_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_SGIX, GL_TRUE);
#endif
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glEnable(GL_TEXTURE_2D);
MakeShadowMatrix(LightPos, SpotDir, SpotAngle, ShadowNear, ShadowFar);
EnableIdentityTexgen();
}
DrawScene();
DisableTexgen();
glDisable(GL_TEXTURE_1D);
glDisable(GL_TEXTURE_2D);
@ -392,16 +494,7 @@ Reshape(int width, int height)
{
WindowWidth = width;
WindowHeight = height;
if (width >= 512 && height >= 512) {
ShadowTexWidth = ShadowTexHeight = 512;
}
else if (width >= 256 && height >= 256) {
ShadowTexWidth = ShadowTexHeight = 256;
}
else {
ShadowTexWidth = ShadowTexHeight = 128;
}
printf("Using %d x %d depth texture\n", ShadowTexWidth, ShadowTexHeight);
NeedNewShadowMap = GL_TRUE;
}
@ -456,8 +549,9 @@ Key(unsigned char key, int x, int y)
DisplayMode = SHOW_DEPTH_MAPPING;
break;
case 'n':
case 's':
case ' ':
DisplayMode = SHOW_NORMAL;
DisplayMode = SHOW_SHADOWS;
break;
case 'o':
if (HaveEXTshadowFuncs) {
@ -465,19 +559,24 @@ Key(unsigned char key, int x, int y)
if (Operator >= 8)
Operator = 0;
printf("Operator: %s\n", OperatorName[Operator]);
#if defined(GL_ARB_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB,
OperatorFunc[Operator]);
#endif
}
break;
case 'p':
UsePackedDepthStencil = !UsePackedDepthStencil;
if (UsePackedDepthStencil
&& !glutExtensionSupported("GL_EXT_packed_depth_stencil")) {
if (UsePackedDepthStencil && !HavePackedDepthStencil) {
printf("Sorry, GL_EXT_packed_depth_stencil not supported\n");
UsePackedDepthStencil = GL_FALSE;
}
else {
printf("Use GL_DEPTH_STENCIL_EXT: %d\n", UsePackedDepthStencil);
/* Don't really need to regenerate shadow map texture, but do so
* to exercise more code more often.
*/
NeedNewShadowMap = GL_TRUE;
}
break;
case 'z':
@ -527,6 +626,9 @@ SpecialKey(int key, int x, int y)
Yrot -= step;
break;
}
if (mod)
NeedNewShadowMap = GL_TRUE;
glutPostRedisplay();
}
@ -539,25 +641,39 @@ Init(void)
#if defined(GL_ARB_depth_texture) && defined(GL_ARB_shadow)
if (!glutExtensionSupported("GL_ARB_depth_texture") ||
!glutExtensionSupported("GL_ARB_shadow")) {
#else
if (1) {
#endif
printf("Sorry, this demo requires the GL_ARB_depth_texture and GL_ARB_shadow extensions\n");
exit(1);
}
printf("Using GL_ARB_depth_texture and GL_ARB_shadow\n");
#elif defined(GL_SGIX_depth_texture) && defined(GL_SGIX_shadow)
if (!glutExtensionSupported("GL_SGIX_depth_texture") ||
!glutExtensionSupported("GL_SGIX_shadow")) {
printf("Sorry, this demo requires the GL_SGIX_depth_texture and GL_SGIX_shadow extensions\n");
exit(1);
#if defined(GL_ARB_shadow_ambient)
HaveShadowAmbient = glutExtensionSupported("GL_ARB_shadow_ambient");
if (HaveShadowAmbient) {
printf("and GL_ARB_shadow_ambient\n");
}
printf("Using GL_SGIX_depth_texture and GL_SGIX_shadow\n");
#endif
HaveEXTshadowFuncs = glutExtensionSupported("GL_EXT_shadow_funcs");
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
HavePackedDepthStencil = glutExtensionSupported("GL_EXT_packed_depth_stencil");
UsePackedDepthStencil = HavePackedDepthStencil;
#if defined(GL_EXT_framebuffer_object)
HaveFBO = glutExtensionSupported("GL_EXT_framebuffer_object");
UseFBO = HaveFBO;
if (UseFBO) {
printf("Using GL_EXT_framebuffer_object\n");
}
#endif
/*
* Set up the 2D shadow map texture
*/
glGenTextures(1, &ShadowTexture);
glBindTexture(GL_TEXTURE_2D, ShadowTexture);
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
@ -565,24 +681,36 @@ Init(void)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
GL_COMPARE_R_TO_TEXTURE_ARB);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB, GL_LEQUAL);
#elif defined(GL_SGIX_shadow)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_OPERATOR_SGIX,
GL_TEXTURE_LEQUAL_R_SGIX);
#endif
if (HaveShadowAmbient) {
#if defined(GL_ARB_shadow_ambient)
if (glutExtensionSupported("GL_ARB_shadow_ambient")) {
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FAIL_VALUE_ARB, 0.3);
printf("and GL_ARB_shadow_ambient\n");
#endif
}
#elif defined(GL_SGIX_shadow_ambient)
if (glutExtensionSupported("GL_SGIX_shadow_ambient")) {
glTexParameterf(GL_TEXTURE_2D, GL_SHADOW_AMBIENT_SGIX, 0.3);
printf("and GL_SGIX_shadow_ambient\n");
#if defined(GL_EXT_framebuffer_object)
if (UseFBO) {
glGenFramebuffersEXT(1, &ShadowFBO);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, ShadowFBO);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
GL_COLOR_ATTACHMENT0_EXT,
GL_RENDERBUFFER_EXT, 0);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
GL_TEXTURE_2D, ShadowTexture, 0);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
}
#endif
/* setup 1-D grayscale texture image for SHOW_DISTANCE mode */
/*
* Setup 1-D grayscale texture image for SHOW_DISTANCE mode
*/
glGenTextures(1, &GrayTexture);
glBindTexture(GL_TEXTURE_1D, GrayTexture);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
{
GLuint i;
GLubyte image[256];