-/* $Id: shadowtex.c,v 1.1 2001/02/20 16:43:50 brianp Exp $ */
-
/*
- * Shadow demo using the GL_SGIX_depth_texture, GL_SGIX_shadow and
- * GL_SGIX_shadow_ambient extensions.
+ * Shadow demo using the GL_ARB_depth_texture, GL_ARB_shadow and
+ * GL_ARB_shadow_ambient extensions (or the old SGIX extensions).
*
* Brian Paul
* 19 Feb 2001
*
+ * Added GL_EXT_shadow_funcs support on 23 March 2002
+ *
* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
*/
+#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
-#include "../util/showbuffer.c"
+#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 GLfloat ShadowNear = 4.0, ShadowFar = 24.0;
static GLint ShadowTexWidth = 256, ShadowTexHeight = 256;
-static GLboolean ShowDepth = GL_FALSE;
-
-static GLfloat ShadowImage[256*256];
+static GLboolean LinearFilter = GL_FALSE;
static GLfloat Bias = -0.06;
static GLboolean Anim = GL_TRUE;
+static GLboolean HaveEXTshadowFuncs = GL_FALSE;
+static GLint Operator = 0;
+static const GLenum OperatorFunc[8] = {
+ GL_LEQUAL, GL_LESS, GL_GEQUAL, GL_GREATER,
+ GL_EQUAL, GL_NOTEQUAL, GL_ALWAYS, GL_NEVER };
+static const char *OperatorName[8] = {
+ "GL_LEQUAL", "GL_LESS", "GL_GEQUAL", "GL_GREATER",
+ "GL_EQUAL", "GL_NOTEQUAL", "GL_ALWAYS", "GL_NEVER" };
+
+
+static GLuint DisplayMode;
+#define SHOW_NORMAL 0
+#define SHOW_DEPTH_IMAGE 1
+#define SHOW_DEPTH_MAPPING 2
+#define SHOW_DISTANCE 3
+
+
static void
DrawScene(void)
* source's point of view.
*/
static void
-ShadowMatrix(const GLfloat lightPos[4], const GLfloat spotDir[3],
- GLfloat spotAngle, GLfloat shadowNear, GLfloat shadowFar)
+MakeShadowMatrix(const GLfloat lightPos[4], const GLfloat spotDir[3],
+ GLfloat spotAngle, GLfloat shadowNear, GLfloat shadowFar)
{
GLfloat d;
static void
-EnableTexgen(void)
+EnableIdentityTexgen(void)
{
/* texgen so that texcoord = vertex coord */
static GLfloat sPlane[4] = { 1, 0, 0, 0 };
}
+/*
+ * Setup 1-D texgen so that the distance from the light source, between
+ * the near and far planes maps to s=0 and s=1. When we draw the scene,
+ * the grayness will indicate the fragment's distance from the light
+ * source.
+ */
+static void
+EnableDistanceTexgen(const GLfloat lightPos[4], const GLfloat lightDir[3],
+ GLfloat lightNear, GLfloat lightFar)
+{
+ GLfloat m, d;
+ GLfloat sPlane[4];
+ GLfloat nearPoint[3];
+
+ m = sqrt(lightDir[0] * lightDir[0] +
+ lightDir[1] * lightDir[1] +
+ lightDir[2] * lightDir[2]);
+
+ d = lightFar - lightNear;
+
+ /* 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;
+
+ sPlane[0] = lightDir[0] / d / m;
+ sPlane[1] = lightDir[1] / d / m;
+ sPlane[2] = lightDir[2] / d / m;
+ sPlane[3] = -(sPlane[0] * nearPoint[0]
+ + sPlane[1] * nearPoint[1]
+ + sPlane[2] * nearPoint[2]);
+
+ glTexGenfv(GL_S, GL_EYE_PLANE, sPlane);
+ glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
+ glEnable(GL_TEXTURE_GEN_S);
+}
+
+
static void
DisableTexgen(void)
{
ComputeLightPos(GLfloat dist, GLfloat latitude, GLfloat longitude,
GLfloat pos[4], GLfloat dir[3])
{
+
pos[0] = dist * sin(longitude * DEG_TO_RAD);
pos[1] = dist * sin(latitude * DEG_TO_RAD);
pos[2] = dist * cos(latitude * DEG_TO_RAD) * cos(longitude * DEG_TO_RAD);
{
GLfloat ar = (GLfloat) WindowWidth / (GLfloat) WindowHeight;
GLfloat d;
+ GLenum error;
ComputeLightPos(LightDist, LightLatitude, LightLongitude,
LightPos, SpotDir);
/*
* Step 2: copy depth buffer into texture map
*/
- glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
- 0, 0, ShadowTexWidth, ShadowTexHeight, 0);
+ if (DisplayMode == SHOW_DEPTH_MAPPING) {
+ /* load depth image as gray-scale luminance texture */
+ GLfloat *depth = (GLfloat *) malloc(ShadowTexWidth * ShadowTexHeight
+ * sizeof(GLfloat));
+ if (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);
+ }
+ }
+ else {
+ /* The normal shadow case */
+ glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
+ 0, 0, ShadowTexWidth, ShadowTexHeight, 0);
+ }
/*
* Step 3: render scene from point of view of the camera
*/
glViewport(0, 0, WindowWidth, 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);
- if (ShowDepth) {
- ShowDepthBuffer(WindowWidth, WindowHeight, 1, 0);
+ if (DisplayMode == SHOW_DEPTH_IMAGE) {
+ ShowDepthBuffer(WindowWidth, WindowHeight, 0, 1);
}
else {
+ 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);
- glEnable(GL_TEXTURE_2D);
- ShadowMatrix(LightPos, SpotDir, SpotAngle, ShadowNear, ShadowFar);
- EnableTexgen();
+ if (LinearFilter) {
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+ }
+ else {
+ 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);
+ MakeShadowMatrix(LightPos, SpotDir, SpotAngle, ShadowNear, ShadowFar);
+ EnableIdentityTexgen();
+ }
+ else if (DisplayMode == SHOW_DISTANCE) {
+ glMatrixMode(GL_TEXTURE);
+ glLoadIdentity();
+ glMatrixMode(GL_MODELVIEW);
+ EnableDistanceTexgen(LightPos, SpotDir, ShadowNear+Bias, ShadowFar);
+ glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
+ glEnable(GL_TEXTURE_1D);
+ }
+ else {
+ assert(DisplayMode == SHOW_NORMAL);
+#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);
}
glutSwapBuffers();
+
+ error = glGetError();
+ if (error) {
+ printf("GL Error: %s\n", (char *) gluErrorString(error));
+ }
}
{
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);
}
static void
Idle(void)
{
- Yrot += 5.0;
+ static double t0 = -1.;
+ double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
+ if (t0 < 0.0)
+ t0 = t;
+ dt = t - t0;
+ t0 = t;
+ Yrot += 75.0 * dt;
/*LightLongitude -= 5.0;*/
glutPostRedisplay();
}
break;
case 'b':
Bias -= 0.01;
+ printf("Bias %g\n", Bias);
break;
case 'B':
Bias += 0.01;
+ printf("Bias %g\n", Bias);
break;
case 'd':
- ShowDepth = !ShowDepth;
+ DisplayMode = SHOW_DISTANCE;
+ break;
+ case 'f':
+ LinearFilter = !LinearFilter;
+ printf("%s filtering\n", LinearFilter ? "Bilinear" : "Nearest");
+ break;
+ case 'i':
+ DisplayMode = SHOW_DEPTH_IMAGE;
+ break;
+ case 'm':
+ DisplayMode = SHOW_DEPTH_MAPPING;
+ break;
+ case 'n':
+ case ' ':
+ DisplayMode = SHOW_NORMAL;
+ break;
+ case 'o':
+ if (HaveEXTshadowFuncs) {
+ Operator++;
+ if (Operator >= 8)
+ Operator = 0;
+ printf("Operator: %s\n", OperatorName[Operator]);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC_ARB,
+ OperatorFunc[Operator]);
+ }
break;
case 'z':
Zrot -= step;
break;
}
glutPostRedisplay();
- printf("Bias %g\n", Bias);
}
static void
Init(void)
{
+#if defined(GL_ARB_depth_texture) && defined(GL_ARB_shadow)
+ if (!glutExtensionSupported("GL_ARB_depth_texture") ||
+ !glutExtensionSupported("GL_ARB_shadow")) {
+ 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);
}
-
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ 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_MIN_FILTER, GL_LINEAR);
+ glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+ glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_SGIX, GL_TRUE);
+#if defined(GL_ARB_shadow)
+ 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 (glutExtensionSupported("GL_SGIX_shadow_ambient"))
+#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");
+ }
+#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");
+ }
+#endif
+
+ /* setup 1-D grayscale texture image for SHOW_DISTANCE mode */
+ {
+ GLuint i;
+ GLubyte image[256];
+ for (i = 0; i < 256; i++)
+ image[i] = i;
+ glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE,
+ 256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, image);
+ }
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
{
printf("Keys:\n");
printf(" a = toggle animation\n");
- printf(" d = toggle display of depth texture\n");
+ printf(" i = show depth texture image\n");
+ printf(" m = show depth texture mapping\n");
+ printf(" d = show fragment distance from light source\n");
+ printf(" n = show normal, shadowed image\n");
+ printf(" f = toggle nearest/bilinear texture filtering\n");
printf(" b/B = decrease/increase shadow map Z bias\n");
printf(" cursor keys = rotate scene\n");
printf(" <shift> + cursor keys = rotate light source\n");
+ if (HaveEXTshadowFuncs)
+ printf(" o = cycle through comparison modes\n");
}
projects / mesa.git / blobdiff