463 lines
12 KiB
C
463 lines
12 KiB
C
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/*
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* Specular reflection demo. The specular highlight is modulated by
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* a sphere-mapped texture. The result is a high-gloss surface.
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* NOTE: you really need hardware acceleration for this.
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* Also note, this technique can't be implemented with multi-texture
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* and separate specular color interpolation because there's no way
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* to indicate that the second texture unit (the reflection map)
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* should modulate the specular color and not the base color.
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* A future multi-texture extension could fix that.
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*
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* Command line options:
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* -info print GL implementation information
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*
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*
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* Brian Paul October 22, 1999 This program is in the public domain.
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*/
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#include <assert.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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#include <string.h>
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#include <GL/glew.h>
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#include <GL/glut.h>
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#include "readtex.h"
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#include "trackball.h"
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#define SPECULAR_TEXTURE_FILE "../images/reflect.rgb"
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#define BASE_TEXTURE_FILE "../images/tile.rgb"
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/* Menu items */
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#define DO_SPEC_TEXTURE 1
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#define OBJECT 2
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#define ANIMATE 3
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#define QUIT 100
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/* for convolution */
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#define FILTER_SIZE 7
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static GLint WinWidth = 500, WinHeight = 500;
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static GLuint CylinderObj = 0;
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static GLuint TeapotObj = 0;
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static GLuint Object = 0;
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static GLboolean Animate = GL_TRUE;
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static float CurQuat[4] = { 0, 0, 0, 1 };
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static GLfloat Black[4] = { 0, 0, 0, 0 };
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static GLfloat White[4] = { 1, 1, 1, 1 };
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static GLfloat Diffuse[4] = { .3, .3, 1.0, 1.0 }; /* blue */
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static GLfloat Shininess = 6;
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static GLuint BaseTexture, SpecularTexture;
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static GLboolean DoSpecTexture = GL_TRUE;
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static GLboolean ButtonDown = GL_FALSE;
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static GLint ButtonX, ButtonY;
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/* performance info */
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static GLint T0 = 0;
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static GLint Frames = 0;
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static void Idle( void )
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{
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static const float yAxis[3] = {0, 1, 0};
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static double t0 = -1.;
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float quat[4];
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double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
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if (t0 < 0.0)
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t0 = t;
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dt = t - t0;
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t0 = t;
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axis_to_quat(yAxis, 2.0 * dt, quat);
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add_quats(quat, CurQuat, CurQuat);
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glutPostRedisplay();
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}
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static void Display( void )
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{
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GLfloat rot[4][4];
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glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
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glPushMatrix();
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build_rotmatrix(rot, CurQuat);
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glMultMatrixf(&rot[0][0]);
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/* First pass: diffuse lighting with base texture */
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glMaterialfv(GL_FRONT, GL_DIFFUSE, Diffuse);
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glMaterialfv(GL_FRONT, GL_SPECULAR, Black);
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glEnable(GL_TEXTURE_2D);
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glBindTexture(GL_TEXTURE_2D, BaseTexture);
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glCallList(Object);
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/* Second pass: specular lighting with reflection texture */
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glEnable(GL_POLYGON_OFFSET_FILL);
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glBlendFunc(GL_ONE, GL_ONE); /* add */
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glEnable(GL_BLEND);
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glMaterialfv(GL_FRONT, GL_DIFFUSE, Black);
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glMaterialfv(GL_FRONT, GL_SPECULAR, White);
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if (DoSpecTexture) {
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glBindTexture(GL_TEXTURE_2D, SpecularTexture);
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glEnable(GL_TEXTURE_GEN_S);
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glEnable(GL_TEXTURE_GEN_T);
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}
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else {
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glDisable(GL_TEXTURE_2D);
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}
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glCallList(Object);
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glDisable(GL_TEXTURE_GEN_S);
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glDisable(GL_TEXTURE_GEN_T);
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glDisable(GL_BLEND);
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glDisable(GL_POLYGON_OFFSET_FILL);
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glPopMatrix();
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glutSwapBuffers();
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if (Animate) {
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GLint t = glutGet(GLUT_ELAPSED_TIME);
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Frames++;
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if (t - T0 >= 5000) {
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GLfloat seconds = (t - T0) / 1000.0;
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GLfloat fps = Frames / seconds;
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printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps);
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T0 = t;
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Frames = 0;
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}
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}
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}
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static void Reshape( int width, int height )
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{
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GLfloat h = 30.0;
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GLfloat w = h * width / height;
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WinWidth = width;
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WinHeight = height;
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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( -w, w, -h, h, 150.0, 500.0 );
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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glTranslatef( 0.0, 0.0, -380.0 );
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}
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static void ToggleAnimate(void)
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{
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Animate = !Animate;
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if (Animate) {
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glutIdleFunc( Idle );
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T0 = glutGet(GLUT_ELAPSED_TIME);
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Frames = 0;
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}
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else {
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glutIdleFunc( NULL );
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}
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}
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static void ModeMenu(int entry)
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{
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if (entry==ANIMATE) {
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ToggleAnimate();
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}
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else if (entry==DO_SPEC_TEXTURE) {
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DoSpecTexture = !DoSpecTexture;
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}
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else if (entry==OBJECT) {
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if (Object == TeapotObj)
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Object = CylinderObj;
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else
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Object = TeapotObj;
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}
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else if (entry==QUIT) {
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exit(0);
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}
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glutPostRedisplay();
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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 's':
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Shininess--;
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if (Shininess < 0.0)
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Shininess = 0.0;
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glMaterialf(GL_FRONT, GL_SHININESS, Shininess);
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printf("Shininess = %g\n", Shininess);
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break;
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case 'S':
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Shininess++;
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if (Shininess > 128.0)
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Shininess = 128.0;
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glMaterialf(GL_FRONT, GL_SHININESS, Shininess);
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printf("Shininess = %g\n", Shininess);
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break;
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case 'a':
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case ' ':
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ToggleAnimate();
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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
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MouseMotion(int x, int y)
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{
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if (ButtonDown) {
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float x0 = (2.0 * ButtonX - WinWidth) / WinWidth;
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float y0 = (WinHeight - 2.0 * ButtonY) / WinHeight;
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float x1 = (2.0 * x - WinWidth) / WinWidth;
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float y1 = (WinHeight - 2.0 * y) / WinHeight;
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float q[4];
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trackball(q, x0, y0, x1, y1);
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ButtonX = x;
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ButtonY = y;
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add_quats(q, CurQuat, CurQuat);
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glutPostRedisplay();
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}
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}
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static void
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MouseButton(int button, int state, int x, int y)
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{
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if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
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ButtonDown = GL_TRUE;
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ButtonX = x;
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ButtonY = y;
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}
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else if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
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ButtonDown = GL_FALSE;
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}
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}
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static void Init( int argc, char *argv[] )
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{
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GLboolean convolve = GL_FALSE;
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GLboolean fullscreen = GL_FALSE;
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int i;
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for (i = 1; i < argc; i++) {
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if (strcmp(argv[i], "-info")==0) {
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printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
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printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
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printf("GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR));
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printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
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}
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else if (strcmp(argv[i], "-c")==0) {
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convolve = GL_TRUE;
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}
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else if (strcmp(argv[i], "-f")==0) {
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fullscreen = GL_TRUE;
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}
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}
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if (fullscreen)
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glutFullScreen();
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/* Cylinder object */
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{
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static GLfloat height = 100.0;
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static GLfloat radius = 40.0;
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static GLint slices = 24; /* pie slices around Z axis */
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static GLint stacks = 10; /* subdivisions along length of cylinder */
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static GLint rings = 4; /* rings in the end disks */
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GLUquadricObj *q = gluNewQuadric();
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assert(q);
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gluQuadricTexture(q, GL_TRUE);
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CylinderObj = glGenLists(1);
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glNewList(CylinderObj, GL_COMPILE);
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glPushMatrix();
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glTranslatef(0.0, 0.0, -0.5 * height);
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glMatrixMode(GL_TEXTURE);
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glLoadIdentity();
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/*glScalef(8.0, 4.0, 2.0);*/
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glMatrixMode(GL_MODELVIEW);
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/* cylinder */
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gluQuadricNormals(q, GL_SMOOTH);
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gluQuadricTexture(q, GL_TRUE);
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gluCylinder(q, radius, radius, height, slices, stacks);
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/* end cap */
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glMatrixMode(GL_TEXTURE);
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glLoadIdentity();
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glScalef(3.0, 3.0, 1.0);
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glMatrixMode(GL_MODELVIEW);
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glTranslatef(0.0, 0.0, height);
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gluDisk(q, 0.0, radius, slices, rings);
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/* other end cap */
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glTranslatef(0.0, 0.0, -height);
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gluQuadricOrientation(q, GLU_INSIDE);
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gluDisk(q, 0.0, radius, slices, rings);
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glPopMatrix();
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glMatrixMode(GL_TEXTURE);
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glLoadIdentity();
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glMatrixMode(GL_MODELVIEW);
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glEndList();
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gluDeleteQuadric(q);
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}
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/* Teapot */
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{
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TeapotObj = glGenLists(1);
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glNewList(TeapotObj, GL_COMPILE);
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glFrontFace(GL_CW);
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glutSolidTeapot(40.0);
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glFrontFace(GL_CCW);
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glEndList();
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}
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/* show cylinder by default */
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Object = CylinderObj;
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/* lighting */
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glEnable(GL_LIGHTING);
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{
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GLfloat pos[4] = { 3, 3, 3, 1 };
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glLightfv(GL_LIGHT0, GL_AMBIENT, Black);
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glLightfv(GL_LIGHT0, GL_DIFFUSE, White);
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glLightfv(GL_LIGHT0, GL_SPECULAR, White);
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glLightfv(GL_LIGHT0, GL_POSITION, pos);
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glEnable(GL_LIGHT0);
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glMaterialfv(GL_FRONT, GL_AMBIENT, Black);
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glMaterialf(GL_FRONT, GL_SHININESS, Shininess);
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glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
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}
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/* Base texture */
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glGenTextures(1, &BaseTexture);
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glBindTexture(GL_TEXTURE_2D, BaseTexture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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if (!LoadRGBMipmaps(BASE_TEXTURE_FILE, GL_RGB)) {
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printf("Error: couldn't load texture image file %s\n", BASE_TEXTURE_FILE);
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exit(1);
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}
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/* Specular texture */
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glGenTextures(1, &SpecularTexture);
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glBindTexture(GL_TEXTURE_2D, SpecularTexture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
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glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
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if (convolve) {
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/* use convolution to blur the texture to simulate a dull finish
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* on the object.
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*/
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GLubyte *img;
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GLenum format;
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GLint w, h;
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GLfloat filter[FILTER_SIZE][FILTER_SIZE][4];
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for (h = 0; h < FILTER_SIZE; h++) {
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for (w = 0; w < FILTER_SIZE; w++) {
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const GLfloat k = 1.0 / (FILTER_SIZE * FILTER_SIZE);
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filter[h][w][0] = k;
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filter[h][w][1] = k;
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filter[h][w][2] = k;
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filter[h][w][3] = k;
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}
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}
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glEnable(GL_CONVOLUTION_2D);
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glConvolutionParameteri(GL_CONVOLUTION_2D,
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GL_CONVOLUTION_BORDER_MODE, GL_CONSTANT_BORDER);
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glConvolutionFilter2D(GL_CONVOLUTION_2D, GL_RGBA,
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FILTER_SIZE, FILTER_SIZE,
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GL_RGBA, GL_FLOAT, filter);
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img = LoadRGBImage(SPECULAR_TEXTURE_FILE, &w, &h, &format);
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if (!img) {
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printf("Error: couldn't load texture image file %s\n",
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SPECULAR_TEXTURE_FILE);
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exit(1);
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}
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0,
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format, GL_UNSIGNED_BYTE, img);
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free(img);
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}
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else {
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/* regular path */
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if (!LoadRGBMipmaps(SPECULAR_TEXTURE_FILE, GL_RGB)) {
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printf("Error: couldn't load texture image file %s\n",
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SPECULAR_TEXTURE_FILE);
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exit(1);
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}
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}
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/* misc */
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glEnable(GL_CULL_FACE);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_DEPTH_TEST);
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glEnable(GL_NORMALIZE);
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glPolygonOffset( -1, -1 );
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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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glutInitWindowSize(WinWidth, WinHeight);
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glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
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glutCreateWindow(argv[0] );
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glewInit();
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glutReshapeFunc( Reshape );
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glutKeyboardFunc( Key );
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glutDisplayFunc( Display );
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glutMotionFunc(MouseMotion);
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glutMouseFunc(MouseButton);
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if (Animate)
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glutIdleFunc( Idle );
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glutCreateMenu(ModeMenu);
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glutAddMenuEntry("Toggle Highlight", DO_SPEC_TEXTURE);
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glutAddMenuEntry("Toggle Object", OBJECT);
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glutAddMenuEntry("Toggle Animate", ANIMATE);
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glutAddMenuEntry("Quit", QUIT);
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glutAttachMenu(GLUT_RIGHT_BUTTON);
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Init(argc, argv);
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glutMainLoop();
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return 0;
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}
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