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| -rw-r--r-- | progs/demos/shadowtex.c | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/progs/demos/shadowtex.c b/progs/demos/shadowtex.c new file mode 100644 index 0000000000..a68ad77a1f --- /dev/null +++ b/progs/demos/shadowtex.c @@ -0,0 +1,393 @@ +/* $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. + * + * Brian Paul + * 19 Feb 2001 + * + * Copyright (C) 1999-2001 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"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included + * in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN + * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + + +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include <GL/glut.h> +#include "../util/showbuffer.c" + + +#define DEG_TO_RAD (3.14159 / 180.0) + +static GLint WindowWidth = 450, WindowHeight = 300; +static GLfloat Xrot = 15, Yrot = 0, Zrot = 0; + +static GLfloat Red[4] = {1, 0, 0, 1}; +static GLfloat Green[4] = {0, 1, 0, 1}; +static GLfloat Blue[4] = {0, 0, 1, 1}; +static GLfloat Yellow[4] = {1, 1, 0, 1}; + +static GLfloat LightDist = 10; +static GLfloat LightLatitude = 45.0; +static GLfloat LightLongitude = 45.0; +static GLfloat LightPos[4]; +static GLfloat SpotDir[3]; +static GLfloat SpotAngle = 40.0 * DEG_TO_RAD; +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 GLfloat Bias = -0.06; + +static GLboolean Anim = GL_TRUE; + + +static void +DrawScene(void) +{ + GLfloat k = 6; + /* sphere */ + glPushMatrix(); + glTranslatef(1.6, 2.2, 2.7); + glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, Green); + glColor4fv(Green); + glutSolidSphere(1.5, 15, 15); + glPopMatrix(); + /* dodecahedron */ + glPushMatrix(); + glTranslatef(-2.0, 1.2, 2.1); + glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, Red); + glColor4fv(Red); + glutSolidDodecahedron(); + glPopMatrix(); + /* icosahedron */ + glPushMatrix(); + glTranslatef(-0.6, 1.3, -0.5); + glScalef(1.5, 1.5, 1.5); + glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, Yellow); + glColor4fv(Red); + glutSolidIcosahedron(); + glPopMatrix(); + /* a plane */ + glPushMatrix(); + glTranslatef(0, -1.1, 0); + glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, Blue); + glColor4fv(Blue); + glNormal3f(0, 1, 0); + glBegin(GL_POLYGON); + glVertex3f(-k, 0, -k); + glVertex3f( k, 0, -k); + glVertex3f( k, 0, k); + glVertex3f(-k, 0, k); + glEnd(); + glPopMatrix(); +} + + +/* + * Load the GL_TEXTURE matrix with the projection from the light + * source's point of view. + */ +static void +ShadowMatrix(const GLfloat lightPos[4], const GLfloat spotDir[3], + GLfloat spotAngle, GLfloat shadowNear, GLfloat shadowFar) +{ + GLfloat d; + + glMatrixMode(GL_TEXTURE); + glLoadIdentity(); + glTranslatef(0.5, 0.5, 0.5 + Bias); + glScalef(0.5, 0.5, 0.5); + d = shadowNear * tan(spotAngle); + glFrustum(-d, d, -d, d, shadowNear, shadowFar); + gluLookAt(lightPos[0], lightPos[1], lightPos[2], + lightPos[0] + spotDir[0], + lightPos[1] + spotDir[1], + lightPos[2] + spotDir[2], + 0, 1, 0); + glMatrixMode(GL_MODELVIEW); +} + + +static void +EnableTexgen(void) +{ + /* texgen so that texcoord = vertex coord */ + static GLfloat sPlane[4] = { 1, 0, 0, 0 }; + static GLfloat tPlane[4] = { 0, 1, 0, 0 }; + static GLfloat rPlane[4] = { 0, 0, 1, 0 }; + static GLfloat qPlane[4] = { 0, 0, 0, 1 }; + + glTexGenfv(GL_S, GL_EYE_PLANE, sPlane); + glTexGenfv(GL_T, GL_EYE_PLANE, tPlane); + glTexGenfv(GL_R, GL_EYE_PLANE, rPlane); + glTexGenfv(GL_Q, GL_EYE_PLANE, qPlane); + glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); + glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); + glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); + glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR); + + glEnable(GL_TEXTURE_GEN_S); + glEnable(GL_TEXTURE_GEN_T); + glEnable(GL_TEXTURE_GEN_R); + glEnable(GL_TEXTURE_GEN_Q); +} + + +static void +DisableTexgen(void) +{ + glDisable(GL_TEXTURE_GEN_S); + glDisable(GL_TEXTURE_GEN_T); + glDisable(GL_TEXTURE_GEN_R); + glDisable(GL_TEXTURE_GEN_Q); +} + + +static 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); + pos[3] = 1; + dir[0] = -pos[0]; + dir[1] = -pos[1]; + dir[2] = -pos[2]; +} + + +static void +Display(void) +{ + GLfloat ar = (GLfloat) WindowWidth / (GLfloat) WindowHeight; + GLfloat d; + + 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); + glMatrixMode(GL_MODELVIEW); + glLoadIdentity(); + gluLookAt(LightPos[0], LightPos[1], LightPos[2], /* from */ + 0, 0, 0, /* target */ + 0, 1, 0); /* up */ + + glViewport(0, 0, ShadowTexWidth, ShadowTexHeight); + glClear(GL_DEPTH_BUFFER_BIT); + DrawScene(); + + /* + * Step 2: copy depth buffer into texture map + */ + 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); + } + else { + 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(); + DrawScene(); + DisableTexgen(); + glDisable(GL_TEXTURE_2D); + } + + glutSwapBuffers(); +} + + +static void +Reshape(int width, int height) +{ + WindowWidth = width; + WindowHeight = height; +} + + +static void +Idle(void) +{ + Yrot += 5.0; + /*LightLongitude -= 5.0;*/ + glutPostRedisplay(); +} + + +static void +Key(unsigned char key, int x, int y) +{ + const GLfloat step = 3.0; + (void) x; + (void) y; + switch (key) { + case 'a': + Anim = !Anim; + if (Anim) + glutIdleFunc(Idle); + else + glutIdleFunc(NULL); + break; + case 'b': + Bias -= 0.01; + break; + case 'B': + Bias += 0.01; + break; + case 'd': + ShowDepth = !ShowDepth; + break; + case 'z': + Zrot -= step; + break; + case 'Z': + Zrot += step; + break; + case 27: + exit(0); + break; + } + glutPostRedisplay(); + printf("Bias %g\n", Bias); +} + + +static void +SpecialKey(int key, int x, int y) +{ + const GLfloat step = 3.0; + const int mod = glutGetModifiers(); + (void) x; + (void) y; + switch (key) { + case GLUT_KEY_UP: + if (mod) + LightLatitude += step; + else + Xrot += step; + break; + case GLUT_KEY_DOWN: + if (mod) + LightLatitude -= step; + else + Xrot -= step; + break; + case GLUT_KEY_LEFT: + if (mod) + LightLongitude += step; + else + Yrot += step; + break; + case GLUT_KEY_RIGHT: + if (mod) + LightLongitude -= step; + else + Yrot -= step; + break; + } + glutPostRedisplay(); +} + + +static void +Init(void) +{ + 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); + 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); + glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_OPERATOR_SGIX, + GL_TEXTURE_LEQUAL_R_SGIX); + + if (glutExtensionSupported("GL_SGIX_shadow_ambient")) + glTexParameterf(GL_TEXTURE_2D, GL_SHADOW_AMBIENT_SGIX, 0.3); + + glEnable(GL_DEPTH_TEST); + glEnable(GL_LIGHTING); + glEnable(GL_LIGHT0); +} + + +static void +PrintHelp(void) +{ + printf("Keys:\n"); + printf(" a = toggle animation\n"); + printf(" d = toggle display of depth texture\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"); +} + + +int +main(int argc, char *argv[]) +{ + glutInit(&argc, argv); + glutInitWindowPosition(0, 0); + glutInitWindowSize(WindowWidth, WindowHeight); + glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH); + glutCreateWindow(argv[0]); + glutReshapeFunc(Reshape); + glutKeyboardFunc(Key); + glutSpecialFunc(SpecialKey); + glutDisplayFunc(Display); + if (Anim) + glutIdleFunc(Idle); + Init(); + PrintHelp(); + glutMainLoop(); + return 0; +} |