412 lines
8.0 KiB
C
412 lines
8.0 KiB
C
/**
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* Procedural Bump Mapping demo. Uses the example shaders from
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* chapter 11 of the OpenGL Shading Language "orange" book.
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* 16 Jan 2007
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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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#include <GL/glut.h>
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#include <GL/glu.h>
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#include <GL/glext.h>
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#include "extfuncs.h"
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static char *FragProgFile = "CH11-bumpmap.frag.txt";
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static char *VertProgFile = "CH11-bumpmap.vert.txt";
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/* program/shader objects */
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static GLuint fragShader;
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static GLuint vertShader;
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static GLuint program;
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struct uniform_info {
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const char *name;
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GLuint size;
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GLint location;
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GLfloat value[4];
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};
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static struct uniform_info Uniforms[] = {
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{ "LightPosition", 3, -1, { 0.57737, 0.57735, 0.57735, 0.0 } },
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{ "SurfaceColor", 3, -1, { 0.8, 0.8, 0.2, 0 } },
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{ "BumpDensity", 1, -1, { 10.0, 0, 0, 0 } },
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{ "BumpSize", 1, -1, { 0.125, 0, 0, 0 } },
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{ "SpecularFactor", 1, -1, { 0.5, 0, 0, 0 } },
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{ NULL, 0, 0, { 0, 0, 0, 0 } }
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};
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static GLint win = 0;
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static GLfloat xRot = 20.0f, yRot = 0.0f, zRot = 0.0f;
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static GLuint tangentAttrib;
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static GLboolean Anim = GL_FALSE;
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static void
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CheckError(int line)
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{
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GLenum err = glGetError();
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if (err) {
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printf("GL Error %s (0x%x) at line %d\n",
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gluErrorString(err), (int) err, line);
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}
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}
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/*
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* Draw a square, specifying normal and tangent vectors.
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*/
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static void
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Square(GLfloat size)
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{
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glNormal3f(0, 0, 1);
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glVertexAttrib3f_func(tangentAttrib, 1, 0, 0);
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glBegin(GL_POLYGON);
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glTexCoord2f(0, 0); glVertex2f(-size, -size);
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glTexCoord2f(1, 0); glVertex2f( size, -size);
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glTexCoord2f(1, 1); glVertex2f( size, size);
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glTexCoord2f(0, 1); glVertex2f(-size, size);
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glEnd();
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}
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static void
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Cube(GLfloat size)
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{
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/* +X */
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glPushMatrix();
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glRotatef(90, 0, 1, 0);
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glTranslatef(0, 0, size);
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Square(size);
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glPopMatrix();
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/* -X */
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glPushMatrix();
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glRotatef(-90, 0, 1, 0);
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glTranslatef(0, 0, size);
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Square(size);
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glPopMatrix();
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/* +Y */
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glPushMatrix();
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glRotatef(90, 1, 0, 0);
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glTranslatef(0, 0, size);
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Square(size);
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glPopMatrix();
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/* -Y */
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glPushMatrix();
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glRotatef(-90, 1, 0, 0);
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glTranslatef(0, 0, size);
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Square(size);
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glPopMatrix();
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/* +Z */
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glPushMatrix();
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glTranslatef(0, 0, size);
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Square(size);
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glPopMatrix();
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/* -Z */
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glPushMatrix();
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glRotatef(180, 0, 1, 0);
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glTranslatef(0, 0, size);
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Square(size);
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glPopMatrix();
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}
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static void
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Idle(void)
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{
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GLint t = glutGet(GLUT_ELAPSED_TIME);
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yRot = t * 0.05;
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glutPostRedisplay();
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}
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static void
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Redisplay(void)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glPushMatrix();
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glRotatef(xRot, 1.0f, 0.0f, 0.0f);
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glRotatef(yRot, 0.0f, 1.0f, 0.0f);
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glRotatef(zRot, 0.0f, 0.0f, 1.0f);
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Cube(1.5);
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glPopMatrix();
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glFinish();
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glFlush();
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CheckError(__LINE__);
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glutSwapBuffers();
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}
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static void
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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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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef(0.0f, 0.0f, -15.0f);
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}
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static void
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CleanUp(void)
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{
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glDeleteShader_func(fragShader);
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glDeleteShader_func(vertShader);
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glDeleteProgram_func(program);
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glutDestroyWindow(win);
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}
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static void
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Key(unsigned char key, int x, int y)
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{
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const GLfloat step = 2.0;
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(void) x;
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(void) y;
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switch(key) {
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case 'a':
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Anim = !Anim;
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glutIdleFunc(Anim ? Idle : NULL);
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break;
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case 'z':
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zRot += step;
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break;
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case 'Z':
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zRot -= step;
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break;
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case 27:
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CleanUp();
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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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SpecialKey(int key, int x, int y)
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{
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const GLfloat step = 2.0;
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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
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LoadAndCompileShader(GLuint shader, const char *text)
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{
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GLint stat;
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glShaderSource_func(shader, 1, (const GLchar **) &text, NULL);
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glCompileShader_func(shader);
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glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat);
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if (!stat) {
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GLchar log[1000];
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GLsizei len;
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glGetShaderInfoLog_func(shader, 1000, &len, log);
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fprintf(stderr, "bump: problem compiling shader: %s\n", log);
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exit(1);
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}
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else {
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printf("Shader compiled OK\n");
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}
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}
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/**
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* Read a shader from a file.
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*/
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static void
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ReadShader(GLuint shader, const char *filename)
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{
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const int max = 100*1000;
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int n;
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char *buffer = (char*) malloc(max);
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FILE *f = fopen(filename, "r");
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if (!f) {
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fprintf(stderr, "bump: Unable to open shader file %s\n", filename);
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exit(1);
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}
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n = fread(buffer, 1, max, f);
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printf("bump: read %d bytes from shader file %s\n", n, filename);
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if (n > 0) {
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buffer[n] = 0;
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LoadAndCompileShader(shader, buffer);
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}
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fclose(f);
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free(buffer);
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}
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static void
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CheckLink(GLuint prog)
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{
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GLint stat;
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glGetProgramiv_func(prog, GL_LINK_STATUS, &stat);
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if (!stat) {
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GLchar log[1000];
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GLsizei len;
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glGetProgramInfoLog_func(prog, 1000, &len, log);
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fprintf(stderr, "Linker error:\n%s\n", log);
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}
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else {
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fprintf(stderr, "Link success!\n");
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}
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}
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static void
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Init(void)
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{
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const char *version;
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GLint i;
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version = (const char *) glGetString(GL_VERSION);
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if (version[0] != '2' || version[1] != '.') {
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printf("Warning: this program expects OpenGL 2.0\n");
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/*exit(1);*/
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}
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printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
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GetExtensionFuncs();
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vertShader = glCreateShader_func(GL_VERTEX_SHADER);
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ReadShader(vertShader, VertProgFile);
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fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
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ReadShader(fragShader, FragProgFile);
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program = glCreateProgram_func();
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glAttachShader_func(program, fragShader);
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glAttachShader_func(program, vertShader);
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glLinkProgram_func(program);
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CheckLink(program);
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glUseProgram_func(program);
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assert(glIsProgram_func(program));
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assert(glIsShader_func(fragShader));
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assert(glIsShader_func(vertShader));
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assert(glGetError() == 0);
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CheckError(__LINE__);
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for (i = 0; Uniforms[i].name; i++) {
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Uniforms[i].location
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= glGetUniformLocation_func(program, Uniforms[i].name);
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printf("Uniform %s location: %d\n", Uniforms[i].name,
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Uniforms[i].location);
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switch (Uniforms[i].size) {
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case 1:
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glUniform1fv_func(Uniforms[i].location, 1, Uniforms[i].value);
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break;
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case 2:
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glUniform2fv_func(Uniforms[i].location, 1, Uniforms[i].value);
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break;
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case 3:
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glUniform3fv_func(Uniforms[i].location, 1, Uniforms[i].value);
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break;
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case 4:
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glUniform4fv_func(Uniforms[i].location, 1, Uniforms[i].value);
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break;
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default:
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abort();
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}
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}
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CheckError(__LINE__);
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tangentAttrib = glGetAttribLocation_func(program, "Tangent");
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printf("Tangent Attrib: %d\n", tangentAttrib);
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assert(tangentAttrib >= 0);
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CheckError(__LINE__);
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glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
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glEnable(GL_DEPTH_TEST);
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glColor3f(1, 0, 0);
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}
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static void
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ParseOptions(int argc, char *argv[])
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{
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int i;
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for (i = 1; i < argc; i++) {
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if (strcmp(argv[i], "-fs") == 0) {
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FragProgFile = argv[i+1];
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}
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else if (strcmp(argv[i], "-vs") == 0) {
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VertProgFile = argv[i+1];
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}
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}
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}
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int
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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(400, 400);
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glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
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win = 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(Redisplay);
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ParseOptions(argc, argv);
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Init();
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glutMainLoop();
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return 0;
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}
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