yet another deriviative of the fplight.c demo for OpenGL 2.0 shading language
This commit is contained in:
Brian Paul
334
progs/demos/fslight.c
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334
progs/demos/fslight.c
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/**
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* Test OpenGL 2.0 vertex/fragment shaders.
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* Brian Paul
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* 1 November 2006
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*
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* Based on ARB version by:
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* Michal Krol
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* 20 February 2006
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*
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* Based on the original demo by:
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* Brian Paul
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* 17 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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#include <GL/gl.h>
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#include <GL/glut.h>
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#include <GL/glext.h>
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static GLfloat diffuse[4] = { 0.5f, 0.5f, 1.0f, 1.0f };
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static GLfloat specular[4] = { 0.8f, 0.8f, 0.8f, 1.0f };
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static GLfloat lightPos[4] = { 0.0f, 10.0f, 20.0f, 1.0f };
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static GLfloat delta = 1.0f;
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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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static GLint uLightPos;
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static GLint uDiffuse;
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static GLint uSpecular;
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static GLint win = 0;
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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 GLint t0 = 0;
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static GLint frames = 0;
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static GLfloat xRot = 0.0f, yRot = 0.0f;
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static PFNGLCREATESHADERPROC glCreateShader_func = NULL;
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static PFNGLSHADERSOURCEPROC glShaderSource_func = NULL;
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static PFNGLGETSHADERSOURCEPROC glGetShaderSource_func = NULL;
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static PFNGLCOMPILESHADERPROC glCompileShader_func = NULL;
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static PFNGLCREATEPROGRAMPROC glCreateProgram_func = NULL;
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static PFNGLDELETEPROGRAMPROC glDeleteProgram_func = NULL;
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static PFNGLDELETESHADERPROC glDeleteShader_func = NULL;
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static PFNGLATTACHSHADERPROC glAttachShader_func = NULL;
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static PFNGLLINKPROGRAMPROC glLinkProgram_func = NULL;
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static PFNGLUSEPROGRAMPROC glUseProgram_func = NULL;
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static PFNGLGETUNIFORMLOCATIONPROC glGetUniformLocation_func = NULL;
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static PFNGLISPROGRAMPROC glIsProgram_func = NULL;
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static PFNGLISSHADERPROC glIsShader_func = NULL;
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static PFNGLUNIFORM3FVPROC glUniform3fv_func = NULL;
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static PFNGLUNIFORM3FVPROC glUniform4fv_func = NULL;
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static void
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normalize(GLfloat *dst, const GLfloat *src)
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{
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GLfloat len = sqrtf(src[0] * src[0] + src[1] * src[1] + src[2] * src[2]);
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dst[0] = src[0] / len;
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dst[1] = src[1] / len;
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dst[2] = src[2] / len;
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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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if (pixelLight) {
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GLfloat vec[3];
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glUseProgram_func(program);
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normalize(vec, lightPos);
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glUniform3fv_func(uLightPos, 1, vec);
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glDisable(GL_LIGHTING);
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}
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else {
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glUseProgram_func(0);
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glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
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glEnable(GL_LIGHTING);
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}
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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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glutSolidSphere(2.0, 10, 5);
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glPopMatrix();
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glutSwapBuffers();
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frames++;
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if (anim) {
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GLint t = glutGet(GLUT_ELAPSED_TIME);
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if (t - t0 >= 5000) {
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GLfloat seconds =(GLfloat)(t - t0) / 1000.0f;
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GLfloat fps = frames / seconds;
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printf("%d frames in %6.3f seconds = %6.3f FPS\n",
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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
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Idle(void)
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{
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lightPos[0] += delta;
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if (lightPos[0] > 25.0f || lightPos[0] < -25.0f)
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delta = -delta;
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glutPostRedisplay();
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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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(void) x;
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(void) y;
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switch(key) {
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case ' ':
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case 'a':
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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] -= 1.0f;
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break;
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case 'X':
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lightPos[0] += 1.0f;
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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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else
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printf("Conventional lighting\n");
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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 = 3.0f;
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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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Init(void)
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{
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static const char *fragShaderText =
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"uniform vec3 lightPos;\n"
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"uniform vec4 diffuse;\n"
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"uniform vec4 specular;\n"
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"varying vec3 normal;\n"
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"void main() {\n"
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" // Compute dot product of light direction and normal vector\n"
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" float dotProd = max(dot(lightPos, normalize(normal)), 0.0);\n"
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" // Compute diffuse and specular contributions\n"
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" gl_FragColor = diffuse * dotProd + specular * pow(dotProd, 20.0);\n"
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"}\n";
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static const char *vertShaderText =
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"varying vec3 normal;\n"
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"void main() {\n"
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" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
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" normal = gl_NormalMatrix * gl_Normal;\n"
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"}\n";
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const char *version;
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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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glCreateShader_func = (PFNGLCREATESHADERPROC) glutGetProcAddress("glCreateShader");
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glDeleteShader_func = (PFNGLDELETESHADERPROC) glutGetProcAddress("glDeleteShader");
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glDeleteProgram_func = (PFNGLDELETEPROGRAMPROC) glutGetProcAddress("glDeleteProgram");
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glShaderSource_func = (PFNGLSHADERSOURCEPROC) glutGetProcAddress("glShaderSource");
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glGetShaderSource_func = (PFNGLGETSHADERSOURCEPROC) glutGetProcAddress("glGetShaderSource");
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glCompileShader_func = (PFNGLCOMPILESHADERPROC) glutGetProcAddress("glCompileShader");
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glCreateProgram_func = (PFNGLCREATEPROGRAMPROC) glutGetProcAddress("glCreateProgram");
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glAttachShader_func = (PFNGLATTACHSHADERPROC) glutGetProcAddress("glAttachShader");
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glLinkProgram_func = (PFNGLLINKPROGRAMPROC) glutGetProcAddress("glLinkProgram");
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glUseProgram_func = (PFNGLUSEPROGRAMPROC) glutGetProcAddress("glUseProgram");
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glGetUniformLocation_func = (PFNGLGETUNIFORMLOCATIONPROC) glutGetProcAddress("glGetUniformLocation");
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glIsProgram_func = (PFNGLISPROGRAMPROC) glutGetProcAddress("glIsProgram");
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glIsShader_func = (PFNGLISSHADERPROC) glutGetProcAddress("glIsShader");
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glUniform3fv_func = (PFNGLUNIFORM3FVPROC) glutGetProcAddress("glUniform3fv");
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glUniform4fv_func = (PFNGLUNIFORM3FVPROC) glutGetProcAddress("glUniform4fv");
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fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
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glShaderSource_func(fragShader, 1, &fragShaderText, NULL);
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glCompileShader_func(fragShader);
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vertShader = glCreateShader_func(GL_VERTEX_SHADER);
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glShaderSource_func(vertShader, 1, &vertShaderText, NULL);
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glCompileShader_func(vertShader);
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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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glUseProgram_func(program);
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uLightPos = glGetUniformLocation_func(program, "lightPos");
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uDiffuse = glGetUniformLocation_func(program, "diffuse");
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uSpecular = glGetUniformLocation_func(program, "specular");
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glUniform4fv_func(uDiffuse, 1, diffuse);
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glUniform4fv_func(uSpecular, 1, specular);
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glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
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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, 20.0f);
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printf("GL_RENDERER = %s\n",(const 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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/* test glGetShaderSource() */
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{
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GLsizei len = strlen(fragShaderText) + 1;
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GLsizei lenOut;
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GLchar *src =(GLchar *) malloc(len * sizeof(GLchar));
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glGetShaderSource_func(fragShader, 0, NULL, src);
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glGetShaderSource_func(fragShader, len, &lenOut, src);
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assert(len == lenOut + 1);
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assert(strcmp(src, fragShaderText) == 0);
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free(src);
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}
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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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}
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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(200, 200);
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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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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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