280 lines
6.8 KiB
C
280 lines
6.8 KiB
C
/*
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* Use GL_NV_fragment_program to implement per-pixel lighting.
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*
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* Brian Paul
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* 7 April 2003
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*/
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#include <assert.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#define GL_GLEXT_PROTOTYPES
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#include <GL/glut.h>
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static GLfloat Diffuse[4] = { 0.5, 0.5, 1.0, 1.0 };
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static GLfloat Specular[4] = { 0.8, 0.8, 0.8, 1.0 };
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static GLfloat LightPos[4] = { 0.0, 10.0, 20.0, 1.0 };
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static GLfloat Delta = 1.0;
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static GLuint FragProg;
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static GLuint VertProg;
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static GLboolean Anim = GL_TRUE;
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static GLboolean Wire = GL_FALSE;
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static GLboolean PixelLight = GL_TRUE;
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static GLfloat Xrot = 0, Yrot = 0;
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#define NAMED_PARAMETER4FV(prog, name, v) \
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glProgramNamedParameter4fvNV(prog, strlen(name), (const GLubyte *) name, v)
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static void Display( void )
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{
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glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
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if (PixelLight) {
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NAMED_PARAMETER4FV(FragProg, "LightPos", LightPos);
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glEnable(GL_FRAGMENT_PROGRAM_NV);
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glEnable(GL_VERTEX_PROGRAM_NV);
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glDisable(GL_LIGHTING);
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}
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else {
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glLightfv(GL_LIGHT0, GL_POSITION, LightPos);
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glDisable(GL_FRAGMENT_PROGRAM_NV);
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glDisable(GL_VERTEX_PROGRAM_NV);
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glEnable(GL_LIGHTING);
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}
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glPushMatrix();
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glRotatef(Xrot, 1, 0, 0);
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glRotatef(Yrot, 0, 1, 0);
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#if 1
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glutSolidSphere(2.0, 10, 5);
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#else
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{
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GLUquadricObj *q = gluNewQuadric();
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gluQuadricNormals(q, GL_SMOOTH);
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gluQuadricTexture(q, GL_TRUE);
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glRotatef(90, 1, 0, 0);
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glTranslatef(0, 0, -1);
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gluCylinder(q, 1.0, 1.0, 2.0, 24, 1);
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gluDeleteQuadric(q);
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}
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#endif
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glPopMatrix();
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glutSwapBuffers();
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}
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static void Idle(void)
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{
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LightPos[0] += Delta;
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if (LightPos[0] > 25.0)
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Delta = -1.0;
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else if (LightPos[0] <- 25.0)
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Delta = 1.0;
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glutPostRedisplay();
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}
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static void Reshape( int width, int height )
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{
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glViewport( 0, 0, width, height );
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glMatrixMode( GL_PROJECTION );
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glLoadIdentity();
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glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
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/*glOrtho( -2.0, 2.0, -2.0, 2.0, 5.0, 25.0 );*/
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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glTranslatef( 0.0, 0.0, -15.0 );
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}
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static void Key( unsigned char key, int x, int y )
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{
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(void) x;
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(void) y;
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switch (key) {
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case ' ':
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Anim = !Anim;
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if (Anim)
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glutIdleFunc(Idle);
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else
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glutIdleFunc(NULL);
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break;
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case 'x':
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LightPos[0] -= 1.0;
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break;
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case 'X':
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LightPos[0] += 1.0;
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break;
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case 'w':
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Wire = !Wire;
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if (Wire)
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glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
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else
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glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
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break;
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case 'p':
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PixelLight = !PixelLight;
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if (PixelLight) {
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printf("Per-pixel lighting\n");
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}
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else {
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printf("Conventional lighting\n");
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}
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break;
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case 27:
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exit(0);
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break;
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}
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glutPostRedisplay();
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}
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static void SpecialKey( int key, int x, int y )
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{
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const GLfloat step = 3.0;
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(void) x;
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(void) y;
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switch (key) {
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case GLUT_KEY_UP:
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Xrot -= step;
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break;
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case GLUT_KEY_DOWN:
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Xrot += step;
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break;
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case GLUT_KEY_LEFT:
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Yrot -= step;
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break;
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case GLUT_KEY_RIGHT:
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Yrot += step;
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break;
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}
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glutPostRedisplay();
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}
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static void Init( void )
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{
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static const char *fragProgramText =
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"!!FP1.0\n"
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"DECLARE Diffuse; \n"
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"DECLARE Specular; \n"
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"DECLARE LightPos; \n"
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"# Compute normalized LightPos, put it in R0\n"
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"DP3 R0.x, LightPos, LightPos;\n"
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"RSQ R0.y, R0.x;\n"
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"MUL R0, LightPos, R0.y;\n"
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"# Compute normalized normal, put it in R1\n"
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"DP3 R1, f[TEX0], f[TEX0]; \n"
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"RSQ R1.y, R1.x;\n"
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"MUL R1, f[TEX0], R1.y;\n"
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"# Compute dot product of light direction and normal vector\n"
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"DP3 R2, R0, R1;"
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"MUL R3, Diffuse, R2; # diffuse attenuation\n"
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"POW R4, R2.x, {20.0}.x; # specular exponent\n"
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"MUL R5, Specular, R4; # specular attenuation\n"
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"ADD o[COLR], R3, R5; # add diffuse and specular colors\n"
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"END \n"
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;
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static const char *vertProgramText =
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"!!VP1.0\n"
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"# typical modelview/projection transform\n"
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"DP4 o[HPOS].x, c[0], v[OPOS] ;\n"
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"DP4 o[HPOS].y, c[1], v[OPOS] ;\n"
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"DP4 o[HPOS].z, c[2], v[OPOS] ;\n"
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"DP4 o[HPOS].w, c[3], v[OPOS] ;\n"
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"# transform normal by inv transpose of modelview, put in tex0\n"
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"DP3 o[TEX0].x, c[4], v[NRML] ;\n"
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"DP3 o[TEX0].y, c[5], v[NRML] ;\n"
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"DP3 o[TEX0].z, c[6], v[NRML] ;\n"
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"DP3 o[TEX0].w, c[7], v[NRML] ;\n"
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"END\n";
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;
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if (!glutExtensionSupported("GL_NV_vertex_program")) {
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printf("Sorry, this demo requires GL_NV_vertex_program\n");
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exit(1);
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}
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if (!glutExtensionSupported("GL_NV_fragment_program")) {
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printf("Sorry, this demo requires GL_NV_fragment_program\n");
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exit(1);
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}
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glGenProgramsNV(1, &FragProg);
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assert(FragProg > 0);
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glGenProgramsNV(1, &VertProg);
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assert(VertProg > 0);
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/*
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* Fragment program
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*/
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glLoadProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg,
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strlen(fragProgramText),
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(const GLubyte *) fragProgramText);
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assert(glIsProgramNV(FragProg));
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glBindProgramNV(GL_FRAGMENT_PROGRAM_NV, FragProg);
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NAMED_PARAMETER4FV(FragProg, "Diffuse", Diffuse);
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NAMED_PARAMETER4FV(FragProg, "Specular", Specular);
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/*
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* Vertex program
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*/
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glLoadProgramNV(GL_VERTEX_PROGRAM_NV, VertProg,
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strlen(vertProgramText),
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(const GLubyte *) vertProgramText);
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assert(glIsProgramNV(VertProg));
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glBindProgramNV(GL_VERTEX_PROGRAM_NV, VertProg);
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glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 0, GL_MODELVIEW_PROJECTION_NV, GL_IDENTITY_NV);
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glTrackMatrixNV(GL_VERTEX_PROGRAM_NV, 4, GL_MODELVIEW, GL_INVERSE_TRANSPOSE_NV);
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/*
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* Misc init
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*/
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glClearColor(0.3, 0.3, 0.3, 0.0);
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glEnable(GL_DEPTH_TEST);
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glEnable(GL_LIGHT0);
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glEnable(GL_LIGHTING);
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glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, Diffuse);
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glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, Specular);
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glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 20.0);
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printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
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printf("Press p to toggle between per-pixel and per-vertex lighting\n");
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}
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int main( int argc, char *argv[] )
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{
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glutInit( &argc, argv );
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glutInitWindowPosition( 0, 0 );
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glutInitWindowSize( 200, 200 );
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glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
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glutCreateWindow(argv[0]);
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glutReshapeFunc( Reshape );
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glutKeyboardFunc( Key );
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glutSpecialFunc( SpecialKey );
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glutDisplayFunc( Display );
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if (Anim)
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glutIdleFunc(Idle);
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Init();
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glutMainLoop();
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return 0;
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}
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