/* Copyright (c) Mark J. Kilgard, 1994, 1997. */ /* This program is freely distributable without licensing fees and is provided without guarantee or warrantee expressed or implied. This program is -not- in the public domain. */ /* Example for PC game developers to show how to *combine* texturing, reflections, and projected shadows all in real-time with OpenGL. Robust reflections use stenciling. Robust projected shadows use both stenciling and polygon offset. PC game programmers should realize that neither stenciling nor polygon offset are supported by Direct3D, so these real-time rendering algorithms are only really viable with OpenGL. The program has modes for disabling the stenciling and polygon offset uses. It is worth running this example with these features toggled off so you can see the sort of artifacts that result. Notice that the floor texturing, reflections, and shadowing all co-exist properly. */ /* When you run this program: Left mouse button controls the view. Middle mouse button controls light position (left & right rotates light around dino; up & down moves light position up and down). Right mouse button pops up menu. */ /* Check out the comments in the "redraw" routine to see how the reflection blending and surface stenciling is done. You can also see in "redraw" how the projected shadows are rendered, including the use of stenciling and polygon offset. */ /* This program is derived from glutdino.c */ /* Compile: cc -o dinoshade dinoshade.c -lglut -lGLU -lGL -lXmu -lXext -lX11 -lm */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <math.h> /* for cos(), sin(), and sqrt() */ #include <stddef.h> /* for ptrdiff_t, referenced by GL.h when GL_GLEXT_LEGACY defined */ #ifdef _WIN32 #include <windows.h> #endif #define GL_GLEXT_LEGACY #include <GL/glew.h> /* OpenGL Utility Toolkit header */ #include <GL/glut.h> /* OpenGL Utility Toolkit header */ /* Some <math.h> files do not define M_PI... */ #ifndef M_PI #define M_PI 3.14159265358979323846 #endif /* Variable controlling various rendering modes. */ static int stencilReflection = 1, stencilShadow = 1, offsetShadow = 1; static int renderShadow = 1, renderDinosaur = 1, renderReflection = 1; static int linearFiltering = 0, useMipmaps = 0, useTexture = 1; static int reportSpeed = 0; static int animation = 1; static GLboolean lightSwitch = GL_TRUE; static int directionalLight = 1; static int forceExtension = 0; /* Time varying or user-controled variables. */ static float jump = 0.0; static float lightAngle = 0.0, lightHeight = 20; GLfloat angle = -150; /* in degrees */ GLfloat angle2 = 30; /* in degrees */ int moving, startx, starty; int lightMoving = 0, lightStartX, lightStartY; enum { MISSING, EXTENSION, ONE_DOT_ONE }; int polygonOffsetVersion; static GLdouble bodyWidth = 3.0; /* *INDENT-OFF* */ static GLfloat body[][2] = { {0, 3}, {1, 1}, {5, 1}, {8, 4}, {10, 4}, {11, 5}, {11, 11.5}, {13, 12}, {13, 13}, {10, 13.5}, {13, 14}, {13, 15}, {11, 16}, {8, 16}, {7, 15}, {7, 13}, {8, 12}, {7, 11}, {6, 6}, {4, 3}, {3, 2}, {1, 2} }; static GLfloat arm[][2] = { {8, 10}, {9, 9}, {10, 9}, {13, 8}, {14, 9}, {16, 9}, {15, 9.5}, {16, 10}, {15, 10}, {15.5, 11}, {14.5, 10}, {14, 11}, {14, 10}, {13, 9}, {11, 11}, {9, 11} }; static GLfloat leg[][2] = { {8, 6}, {8, 4}, {9, 3}, {9, 2}, {8, 1}, {8, 0.5}, {9, 0}, {12, 0}, {10, 1}, {10, 2}, {12, 4}, {11, 6}, {10, 7}, {9, 7} }; static GLfloat eye[][2] = { {8.75, 15}, {9, 14.7}, {9.6, 14.7}, {10.1, 15}, {9.6, 15.25}, {9, 15.25} }; static GLfloat lightPosition[4]; static GLfloat lightColor[] = {0.8, 1.0, 0.8, 1.0}; /* green-tinted */ static GLfloat skinColor[] = {0.1, 1.0, 0.1, 1.0}, eyeColor[] = {1.0, 0.2, 0.2, 1.0}; /* *INDENT-ON* */ /* Nice floor texture tiling pattern. */ static char *circles[] = { "....xxxx........", "..xxxxxxxx......", ".xxxxxxxxxx.....", ".xxx....xxx.....", "xxx......xxx....", "xxx......xxx....", "xxx......xxx....", "xxx......xxx....", ".xxx....xxx.....", ".xxxxxxxxxx.....", "..xxxxxxxx......", "....xxxx........", "................", "................", "................", "................", }; static void makeFloorTexture(void) { GLubyte floorTexture[16][16][3]; GLubyte *loc; int s, t; /* Setup RGB image for the texture. */ loc = (GLubyte*) floorTexture; for (t = 0; t < 16; t++) { for (s = 0; s < 16; s++) { if (circles[t][s] == 'x') { /* Nice green. */ loc[0] = 0x1f; loc[1] = 0x8f; loc[2] = 0x1f; } else { /* Light gray. */ loc[0] = 0xaa; loc[1] = 0xaa; loc[2] = 0xaa; } loc += 3; } } glPixelStorei(GL_UNPACK_ALIGNMENT, 1); if (useMipmaps) { glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); gluBuild2DMipmaps(GL_TEXTURE_2D, 3, 16, 16, GL_RGB, GL_UNSIGNED_BYTE, floorTexture); } else { if (linearFiltering) { glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); } else { glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); } glTexImage2D(GL_TEXTURE_2D, 0, 3, 16, 16, 0, GL_RGB, GL_UNSIGNED_BYTE, floorTexture); } } enum { X, Y, Z, W }; enum { A, B, C, D }; /* Create a matrix that will project the desired shadow. */ static void shadowMatrix(GLfloat shadowMat[4][4], GLfloat groundplane[4], GLfloat lightpos[4]) { GLfloat dot; /* Find dot product between light position vector and ground plane normal. */ dot = groundplane[X] * lightpos[X] + groundplane[Y] * lightpos[Y] + groundplane[Z] * lightpos[Z] + groundplane[W] * lightpos[W]; shadowMat[0][0] = dot - lightpos[X] * groundplane[X]; shadowMat[1][0] = 0.f - lightpos[X] * groundplane[Y]; shadowMat[2][0] = 0.f - lightpos[X] * groundplane[Z]; shadowMat[3][0] = 0.f - lightpos[X] * groundplane[W]; shadowMat[X][1] = 0.f - lightpos[Y] * groundplane[X]; shadowMat[1][1] = dot - lightpos[Y] * groundplane[Y]; shadowMat[2][1] = 0.f - lightpos[Y] * groundplane[Z]; shadowMat[3][1] = 0.f - lightpos[Y] * groundplane[W]; shadowMat[X][2] = 0.f - lightpos[Z] * groundplane[X]; shadowMat[1][2] = 0.f - lightpos[Z] * groundplane[Y]; shadowMat[2][2] = dot - lightpos[Z] * groundplane[Z]; shadowMat[3][2] = 0.f - lightpos[Z] * groundplane[W]; shadowMat[X][3] = 0.f - lightpos[W] * groundplane[X]; shadowMat[1][3] = 0.f - lightpos[W] * groundplane[Y]; shadowMat[2][3] = 0.f - lightpos[W] * groundplane[Z]; shadowMat[3][3] = dot - lightpos[W] * groundplane[W]; } /* Find the plane equation given 3 points. */ static void findPlane(GLfloat plane[4], GLfloat v0[3], GLfloat v1[3], GLfloat v2[3]) { GLfloat vec0[3], vec1[3]; /* Need 2 vectors to find cross product. */ vec0[X] = v1[X] - v0[X]; vec0[Y] = v1[Y] - v0[Y]; vec0[Z] = v1[Z] - v0[Z]; vec1[X] = v2[X] - v0[X]; vec1[Y] = v2[Y] - v0[Y]; vec1[Z] = v2[Z] - v0[Z]; /* find cross product to get A, B, and C of plane equation */ plane[A] = vec0[Y] * vec1[Z] - vec0[Z] * vec1[Y]; plane[B] = -(vec0[X] * vec1[Z] - vec0[Z] * vec1[X]); plane[C] = vec0[X] * vec1[Y] - vec0[Y] * vec1[X]; plane[D] = -(plane[A] * v0[X] + plane[B] * v0[Y] + plane[C] * v0[Z]); } static void extrudeSolidFromPolygon(GLfloat data[][2], unsigned int dataSize, GLdouble thickness, GLuint side, GLuint edge, GLuint whole) { static GLUtriangulatorObj *tobj = NULL; GLdouble vertex[3], dx, dy, len; int i; int count = (int) (dataSize / (2 * sizeof(GLfloat))); if (tobj == NULL) { tobj = gluNewTess(); /* create and initialize a GLU polygon tesselation object */ gluTessCallback(tobj, GLU_BEGIN, glBegin); gluTessCallback(tobj, GLU_VERTEX, glVertex2fv); /* semi-tricky */ gluTessCallback(tobj, GLU_END, glEnd); } glNewList(side, GL_COMPILE); glShadeModel(GL_SMOOTH); /* smooth minimizes seeing tessellation */ gluBeginPolygon(tobj); for (i = 0; i < count; i++) { vertex[0] = data[i][0]; vertex[1] = data[i][1]; vertex[2] = 0; gluTessVertex(tobj, vertex, data[i]); } gluEndPolygon(tobj); glEndList(); glNewList(edge, GL_COMPILE); glShadeModel(GL_FLAT); /* flat shade keeps angular hands from being "smoothed" */ glBegin(GL_QUAD_STRIP); for (i = 0; i <= count; i++) { #if 1 /* weird, but seems to be legal */ /* mod function handles closing the edge */ glVertex3f(data[i % count][0], data[i % count][1], 0.0); glVertex3f(data[i % count][0], data[i % count][1], thickness); /* Calculate a unit normal by dividing by Euclidean distance. We * could be lazy and use glEnable(GL_NORMALIZE) so we could pass in * arbitrary normals for a very slight performance hit. */ dx = data[(i + 1) % count][1] - data[i % count][1]; dy = data[i % count][0] - data[(i + 1) % count][0]; len = sqrt(dx * dx + dy * dy); glNormal3f(dx / len, dy / len, 0.0); #else /* the nice way of doing it */ /* Calculate a unit normal by dividing by Euclidean distance. We * could be lazy and use glEnable(GL_NORMALIZE) so we could pass in * arbitrary normals for a very slight performance hit. */ dx = data[i % count][1] - data[(i - 1 + count) % count][1]; dy = data[(i - 1 + count) % count][0] - data[i % count][0]; len = sqrt(dx * dx + dy * dy); glNormal3f(dx / len, dy / len, 0.0); /* mod function handles closing the edge */ glVertex3f(data[i % count][0], data[i % count][1], 0.0); glVertex3f(data[i % count][0], data[i % count][1], thickness); #endif } glEnd(); glEndList(); glNewList(whole, GL_COMPILE); glFrontFace(GL_CW); glCallList(edge); glNormal3f(0.0, 0.0, -1.0); /* constant normal for side */ glCallList(side); glPushMatrix(); glTranslatef(0.0, 0.0, thickness); glFrontFace(GL_CCW); glNormal3f(0.0, 0.0, 1.0); /* opposite normal for other side */ glCallList(side); glPopMatrix(); glEndList(); } /* Enumerants for refering to display lists. */ typedef enum { RESERVED, BODY_SIDE, BODY_EDGE, BODY_WHOLE, ARM_SIDE, ARM_EDGE, ARM_WHOLE, LEG_SIDE, LEG_EDGE, LEG_WHOLE, EYE_SIDE, EYE_EDGE, EYE_WHOLE } displayLists; static void makeDinosaur(void) { extrudeSolidFromPolygon(body, sizeof(body), bodyWidth, BODY_SIDE, BODY_EDGE, BODY_WHOLE); extrudeSolidFromPolygon(arm, sizeof(arm), bodyWidth / 4, ARM_SIDE, ARM_EDGE, ARM_WHOLE); extrudeSolidFromPolygon(leg, sizeof(leg), bodyWidth / 2, LEG_SIDE, LEG_EDGE, LEG_WHOLE); extrudeSolidFromPolygon(eye, sizeof(eye), bodyWidth + 0.2, EYE_SIDE, EYE_EDGE, EYE_WHOLE); } static void drawDinosaur(void) { glPushMatrix(); /* Translate the dinosaur to be at (0,8,0). */ glTranslatef(-8, 0, -bodyWidth / 2); glTranslatef(0.0, jump, 0.0); glMaterialfv(GL_FRONT, GL_DIFFUSE, skinColor); glCallList(BODY_WHOLE); glTranslatef(0.0, 0.0, bodyWidth); glCallList(ARM_WHOLE); glCallList(LEG_WHOLE); glTranslatef(0.0, 0.0, -bodyWidth - bodyWidth / 4); glCallList(ARM_WHOLE); glTranslatef(0.0, 0.0, -bodyWidth / 4); glCallList(LEG_WHOLE); glTranslatef(0.0, 0.0, bodyWidth / 2 - 0.1); glMaterialfv(GL_FRONT, GL_DIFFUSE, eyeColor); glCallList(EYE_WHOLE); glPopMatrix(); } static GLfloat floorVertices[4][3] = { { -20.0, 0.0, 20.0 }, { 20.0, 0.0, 20.0 }, { 20.0, 0.0, -20.0 }, { -20.0, 0.0, -20.0 }, }; /* Draw a floor (possibly textured). */ static void drawFloor(void) { glDisable(GL_LIGHTING); if (useTexture) { glEnable(GL_TEXTURE_2D); } glBegin(GL_QUADS); glTexCoord2f(0.0, 0.0); glVertex3fv(floorVertices[0]); glTexCoord2f(0.0, 16.0); glVertex3fv(floorVertices[1]); glTexCoord2f(16.0, 16.0); glVertex3fv(floorVertices[2]); glTexCoord2f(16.0, 0.0); glVertex3fv(floorVertices[3]); glEnd(); if (useTexture) { glDisable(GL_TEXTURE_2D); } glEnable(GL_LIGHTING); } static GLfloat floorPlane[4]; static GLfloat floorShadow[4][4]; static void redraw(void) { int start = 0, end = 0; if (reportSpeed) { start = glutGet(GLUT_ELAPSED_TIME); } /* Clear; default stencil clears to zero. */ if ((stencilReflection && renderReflection) || (stencilShadow && renderShadow)) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); } else { /* Avoid clearing stencil when not using it. */ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); } /* Reposition the light source. */ lightPosition[0] = 12*cos(lightAngle); lightPosition[1] = lightHeight; lightPosition[2] = 12*sin(lightAngle); if (directionalLight) { lightPosition[3] = 0.0; } else { lightPosition[3] = 1.0; } shadowMatrix(floorShadow, floorPlane, lightPosition); glPushMatrix(); /* Perform scene rotations based on user mouse input. */ glRotatef(angle2, 1.0, 0.0, 0.0); glRotatef(angle, 0.0, 1.0, 0.0); /* Tell GL new light source position. */ glLightfv(GL_LIGHT0, GL_POSITION, lightPosition); if (renderReflection) { if (stencilReflection) { /* We can eliminate the visual "artifact" of seeing the "flipped" dinosaur underneath the floor by using stencil. The idea is draw the floor without color or depth update but so that a stencil value of one is where the floor will be. Later when rendering the dinosaur reflection, we will only update pixels with a stencil value of 1 to make sure the reflection only lives on the floor, not below the floor. */ /* Don't update color or depth. */ glDisable(GL_DEPTH_TEST); glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE); /* Draw 1 into the stencil buffer. */ glEnable(GL_STENCIL_TEST); glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE); glStencilFunc(GL_ALWAYS, 1, 0xffffffff); /* Now render floor; floor pixels just get their stencil set to 1. */ drawFloor(); /* Re-enable update of color and depth. */ glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); glEnable(GL_DEPTH_TEST); /* Now, only render where stencil is set to 1. */ glStencilFunc(GL_EQUAL, 1, 0xffffffff); /* draw if ==1 */ glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP); } glPushMatrix(); /* The critical reflection step: Reflect dinosaur through the floor (the Y=0 plane) to make a relection. */ glScalef(1.0, -1.0, 1.0); /* Reflect the light position. */ glLightfv(GL_LIGHT0, GL_POSITION, lightPosition); /* To avoid our normals getting reversed and hence botched lighting on the reflection, turn on normalize. */ glEnable(GL_NORMALIZE); glCullFace(GL_FRONT); /* Draw the reflected dinosaur. */ drawDinosaur(); /* Disable noramlize again and re-enable back face culling. */ glDisable(GL_NORMALIZE); glCullFace(GL_BACK); glPopMatrix(); /* Switch back to the unreflected light position. */ glLightfv(GL_LIGHT0, GL_POSITION, lightPosition); if (stencilReflection) { glDisable(GL_STENCIL_TEST); } } /* Back face culling will get used to only draw either the top or the bottom floor. This let's us get a floor with two distinct appearances. The top floor surface is reflective and kind of red. The bottom floor surface is not reflective and blue. */ /* Draw "bottom" of floor in blue. */ glFrontFace(GL_CW); /* Switch face orientation. */ glColor4f(0.1, 0.1, 0.7, 1.0); drawFloor(); glFrontFace(GL_CCW); if (renderShadow) { if (stencilShadow) { /* Draw the floor with stencil value 3. This helps us only draw the shadow once per floor pixel (and only on the floor pixels). */ glEnable(GL_STENCIL_TEST); glStencilFunc(GL_ALWAYS, 3, 0xffffffff); glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE); } } /* Draw "top" of floor. Use blending to blend in reflection. */ glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glColor4f(0.7, 0.0, 0.0, 0.3); glColor4f(1.0, 1.0, 1.0, 0.3); drawFloor(); glDisable(GL_BLEND); if (renderDinosaur) { /* Draw "actual" dinosaur, not its reflection. */ drawDinosaur(); } if (renderShadow) { /* Render the projected shadow. */ if (stencilShadow) { /* Now, only render where stencil is set above 2 (ie, 3 where the top floor is). Update stencil with 2 where the shadow gets drawn so we don't redraw (and accidently reblend) the shadow). */ glStencilFunc(GL_LESS, 2, 0xffffffff); /* draw if ==1 */ glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE); } /* To eliminate depth buffer artifacts, we use polygon offset to raise the depth of the projected shadow slightly so that it does not depth buffer alias with the floor. */ if (offsetShadow) { switch (polygonOffsetVersion) { case EXTENSION: #ifdef GL_EXT_polygon_offset glEnable(GL_POLYGON_OFFSET_EXT); break; #endif #ifdef GL_VERSION_1_1 case ONE_DOT_ONE: glEnable(GL_POLYGON_OFFSET_FILL); break; #endif case MISSING: /* Oh well. */ break; } } /* Render 50% black shadow color on top of whatever the floor appareance is. */ glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glDisable(GL_LIGHTING); /* Force the 50% black. */ glColor4f(0.0, 0.0, 0.0, 0.5); glPushMatrix(); /* Project the shadow. */ glMultMatrixf((GLfloat *) floorShadow); drawDinosaur(); glPopMatrix(); glDisable(GL_BLEND); glEnable(GL_LIGHTING); if (offsetShadow) { switch (polygonOffsetVersion) { #ifdef GL_EXT_polygon_offset case EXTENSION: glDisable(GL_POLYGON_OFFSET_EXT); break; #endif #ifdef GL_VERSION_1_1 case ONE_DOT_ONE: glDisable(GL_POLYGON_OFFSET_FILL); break; #endif case MISSING: /* Oh well. */ break; } } if (stencilShadow) { glDisable(GL_STENCIL_TEST); } } glPushMatrix(); glDisable(GL_LIGHTING); glColor3f(1.0, 1.0, 0.0); if (directionalLight) { /* Draw an arrowhead. */ glDisable(GL_CULL_FACE); glTranslatef(lightPosition[0], lightPosition[1], lightPosition[2]); glRotatef(lightAngle * -180.0 / M_PI, 0, 1, 0); glRotatef(atan(lightHeight/12) * 180.0 / M_PI, 0, 0, 1); glBegin(GL_TRIANGLE_FAN); glVertex3f(0, 0, 0); glVertex3f(2, 1, 1); glVertex3f(2, -1, 1); glVertex3f(2, -1, -1); glVertex3f(2, 1, -1); glVertex3f(2, 1, 1); glEnd(); /* Draw a white line from light direction. */ glColor3f(1.0, 1.0, 1.0); glBegin(GL_LINES); glVertex3f(0, 0, 0); glVertex3f(5, 0, 0); glEnd(); glEnable(GL_CULL_FACE); } else { /* Draw a yellow ball at the light source. */ glTranslatef(lightPosition[0], lightPosition[1], lightPosition[2]); glutSolidSphere(1.0, 5, 5); } glEnable(GL_LIGHTING); glPopMatrix(); glPopMatrix(); if (reportSpeed) { glFinish(); end = glutGet(GLUT_ELAPSED_TIME); printf("Speed %.3g frames/sec (%d ms)\n", 1000.0/(end-start), end-start); fflush(stdout); } glutSwapBuffers(); } /* ARGSUSED2 */ static void mouse(int button, int state, int x, int y) { if (button == GLUT_LEFT_BUTTON) { if (state == GLUT_DOWN) { moving = 1; startx = x; starty = y; } if (state == GLUT_UP) { moving = 0; } } if (button == GLUT_MIDDLE_BUTTON) { if (state == GLUT_DOWN) { lightMoving = 1; lightStartX = x; lightStartY = y; } if (state == GLUT_UP) { lightMoving = 0; } } } /* ARGSUSED1 */ static void motion(int x, int y) { if (moving) { angle = angle + (x - startx); angle2 = angle2 + (y - starty); startx = x; starty = y; glutPostRedisplay(); } if (lightMoving) { lightAngle += (x - lightStartX)/40.0; lightHeight += (lightStartY - y)/20.0; lightStartX = x; lightStartY = y; glutPostRedisplay(); } } /* Advance time varying state when idle callback registered. */ static void idle(void) { static float time = 0.0; time = glutGet(GLUT_ELAPSED_TIME) / 500.0; jump = 4.0 * fabs(sin(time)*0.5); if (!lightMoving) { lightAngle += 0.03; } glutPostRedisplay(); } enum { M_NONE, M_MOTION, M_LIGHT, M_TEXTURE, M_SHADOWS, M_REFLECTION, M_DINOSAUR, M_STENCIL_REFLECTION, M_STENCIL_SHADOW, M_OFFSET_SHADOW, M_POSITIONAL, M_DIRECTIONAL, M_PERFORMANCE }; static void controlLights(int value) { switch (value) { case M_NONE: return; case M_MOTION: animation = 1 - animation; if (animation) { glutIdleFunc(idle); } else { glutIdleFunc(NULL); } break; case M_LIGHT: lightSwitch = !lightSwitch; if (lightSwitch) { glEnable(GL_LIGHT0); } else { glDisable(GL_LIGHT0); } break; case M_TEXTURE: useTexture = !useTexture; break; case M_SHADOWS: renderShadow = 1 - renderShadow; break; case M_REFLECTION: renderReflection = 1 - renderReflection; break; case M_DINOSAUR: renderDinosaur = 1 - renderDinosaur; break; case M_STENCIL_REFLECTION: stencilReflection = 1 - stencilReflection; break; case M_STENCIL_SHADOW: stencilShadow = 1 - stencilShadow; break; case M_OFFSET_SHADOW: offsetShadow = 1 - offsetShadow; break; case M_POSITIONAL: directionalLight = 0; break; case M_DIRECTIONAL: directionalLight = 1; break; case M_PERFORMANCE: reportSpeed = 1 - reportSpeed; break; } glutPostRedisplay(); } /* When not visible, stop animating. Restart when visible again. */ static void visible(int vis) { if (vis == GLUT_VISIBLE) { if (animation) glutIdleFunc(idle); } else { if (!animation) glutIdleFunc(NULL); } } /* Press any key to redraw; good when motion stopped and performance reporting on. */ /* ARGSUSED */ static void key(unsigned char c, int x, int y) { if (c == 27) { exit(0); /* IRIS GLism, Escape quits. */ } glutPostRedisplay(); } /* Press any key to redraw; good when motion stopped and performance reporting on. */ /* ARGSUSED */ static void special(int k, int x, int y) { glutPostRedisplay(); } static int supportsOneDotOne(void) { const char *version; int major, minor; version = (char *) glGetString(GL_VERSION); if (sscanf(version, "%d.%d", &major, &minor) == 2) return major * 10 + minor >= 11; return 0; /* OpenGL version string malformed! */ } int main(int argc, char **argv) { int i; glutInit(&argc, argv); for (i=1; i<argc; i++) { if (!strcmp("-linear", argv[i])) { linearFiltering = 1; } else if (!strcmp("-mipmap", argv[i])) { useMipmaps = 1; } else if (!strcmp("-ext", argv[i])) { forceExtension = 1; } } glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_STENCIL); #if 0 /* In GLUT 4.0, you'll be able to do this an be sure to get 2 bits of stencil if the machine has it for you. */ glutInitDisplayString("samples stencil>=2 rgb double depth"); #endif glutCreateWindow("Shadowy Leapin' Lizards"); glewInit(); if (glutGet(GLUT_WINDOW_STENCIL_SIZE) <= 1) { printf("dinoshade: Sorry, I need at least 2 bits of stencil.\n"); exit(1); } /* Register GLUT callbacks. */ glutDisplayFunc(redraw); glutMouseFunc(mouse); glutMotionFunc(motion); glutVisibilityFunc(visible); glutKeyboardFunc(key); glutSpecialFunc(special); glutCreateMenu(controlLights); glutAddMenuEntry("Toggle motion", M_MOTION); glutAddMenuEntry("-----------------------", M_NONE); glutAddMenuEntry("Toggle light", M_LIGHT); glutAddMenuEntry("Toggle texture", M_TEXTURE); glutAddMenuEntry("Toggle shadows", M_SHADOWS); glutAddMenuEntry("Toggle reflection", M_REFLECTION); glutAddMenuEntry("Toggle dinosaur", M_DINOSAUR); glutAddMenuEntry("-----------------------", M_NONE); glutAddMenuEntry("Toggle reflection stenciling", M_STENCIL_REFLECTION); glutAddMenuEntry("Toggle shadow stenciling", M_STENCIL_SHADOW); glutAddMenuEntry("Toggle shadow offset", M_OFFSET_SHADOW); glutAddMenuEntry("----------------------", M_NONE); glutAddMenuEntry("Positional light", M_POSITIONAL); glutAddMenuEntry("Directional light", M_DIRECTIONAL); glutAddMenuEntry("-----------------------", M_NONE); glutAddMenuEntry("Toggle performance", M_PERFORMANCE); glutAttachMenu(GLUT_RIGHT_BUTTON); makeDinosaur(); #ifdef GL_VERSION_1_1 if (supportsOneDotOne() && !forceExtension) { polygonOffsetVersion = ONE_DOT_ONE; glPolygonOffset(-2.0, -9.0); } else #endif { #ifdef GL_EXT_polygon_offset /* check for the polygon offset extension */ if (glutExtensionSupported("GL_EXT_polygon_offset")) { polygonOffsetVersion = EXTENSION; glPolygonOffsetEXT(-2.0, -0.002); } else #endif { polygonOffsetVersion = MISSING; printf("\ndinoshine: Missing polygon offset.\n"); printf(" Expect shadow depth aliasing artifacts.\n\n"); fflush(stdout); } } glEnable(GL_CULL_FACE); glEnable(GL_DEPTH_TEST); glEnable(GL_TEXTURE_2D); glLineWidth(3.0); glMatrixMode(GL_PROJECTION); gluPerspective( /* field of view in degree */ 40.0, /* aspect ratio */ 1.0, /* Z near */ 20.0, /* Z far */ 100.0); glMatrixMode(GL_MODELVIEW); gluLookAt(0.0, 8.0, 60.0, /* eye is at (0,8,60) */ 0.0, 8.0, 0.0, /* center is at (0,8,0) */ 0.0, 1.0, 0.); /* up is in postivie Y direction */ glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1); glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColor); glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.1); glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05); glEnable(GL_LIGHT0); glEnable(GL_LIGHTING); makeFloorTexture(); /* Setup floor plane for projected shadow calculations. */ findPlane(floorPlane, floorVertices[1], floorVertices[2], floorVertices[3]); glutMainLoop(); return 0; /* ANSI C requires main to return int. */ }