diff options
Diffstat (limited to 'progs/demos')
| -rw-r--r-- | progs/demos/Makefile | 1 | ||||
| -rw-r--r-- | progs/demos/dinoshade.c | 912 |
2 files changed, 913 insertions, 0 deletions
diff --git a/progs/demos/Makefile b/progs/demos/Makefile index 2fe407972d7..8febc14d410 100644 --- a/progs/demos/Makefile +++ b/progs/demos/Makefile @@ -19,6 +19,7 @@ PROGS = \ clearspd \ copypix \ cubemap \ + dinoshade \ drawpix \ engine \ fbo_firecube \ diff --git a/progs/demos/dinoshade.c b/progs/demos/dinoshade.c new file mode 100644 index 00000000000..451da2ec895 --- /dev/null +++ b/progs/demos/dinoshade.c @@ -0,0 +1,912 @@ + +/* 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, end; + + 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); + } + + 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"); + } + } + + 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. */ +} |