Added new directory of GL shading language demos: glsl

1 files changed, 317 insertions, 0 deletions

diff --git a/progs/glsl/mandelbrot.c b/progs/glsl/mandelbrot.c
new file mode 100644
index 00000000000..a6c326bfa0c
--- /dev/null
+++ b/progs/glsl/mandelbrot.c
@@ -0,0 +1,317 @@
+/**
+ * "Mandelbrot" shader demo.  Uses the example shaders from
+ * chapter 15 (or 18) of the OpenGL Shading Language "orange" book.
+ * 15 Jan 2007
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/gl.h>
+#include <GL/glut.h>
+#include <GL/glext.h>
+#include "extfuncs.h"
+
+
+static char *FragProgFile = "CH18-mandel.frag.txt";
+static char *VertProgFile = "CH18-mandel.vert.txt";
+
+/* program/shader objects */
+static GLuint fragShader;
+static GLuint vertShader;
+static GLuint program;
+
+
+struct uniform_info {
+   const char *name;
+   GLuint size;
+   GLint location;
+   GLfloat value[4];
+};
+
+static struct uniform_info Uniforms[] = {
+   /* vert */
+   { "LightPosition",        3, -1, { 0.1, 0.1, 9.0, 0} },
+   { "SpecularContribution", 1, -1, { 0.5, 0, 0, 0 } },
+   { "DiffuseContribution",  1, -1, { 0.5, 0, 0, 0 } },
+   { "Shininess",            1, -1, { 20.0, 0, 0, 0 } },
+   /* frag */
+   { "MaxIterations",        1, -1, { 12, 0, 0, 0 } },
+   { "Zoom",                 1, -1, { 0.5, 0, 0, 0 } },
+   { "Xcenter",              1, -1, { -1.0, 0, 0, 0 } },
+   { "Ycenter",              1, -1, { .005, 0, 0, 0 } },
+   { "InnerColor",           3, -1, { 1, 0, 0, 0 } },
+   { "OuterColor1",          3, -1, { 0, 1, 0, 0 } },
+   { "OuterColor2",          3, -1, { 0, 0, 1, 0 } },
+   { NULL, 0, 0, { 0, 0, 0, 0 } }
+};
+
+static GLint win = 0;
+
+
+static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f;
+
+
+
+
+static void
+Redisplay(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+   
+   glPushMatrix();
+   glRotatef(xRot, 1.0f, 0.0f, 0.0f);
+   glRotatef(yRot, 0.0f, 1.0f, 0.0f);
+   glRotatef(zRot, 0.0f, 0.0f, 1.0f);
+
+   glBegin(GL_POLYGON);
+   glTexCoord2f(0, 0);   glVertex2f(-1, -1);
+   glTexCoord2f(1, 0);   glVertex2f( 1, -1);
+   glTexCoord2f(1, 1);   glVertex2f( 1,  1);
+   glTexCoord2f(0, 1);   glVertex2f(-1,  1);
+   glEnd();
+
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0f, 0.0f, -6.0f);
+}
+
+
+static void
+CleanUp(void)
+{
+   glDeleteShader_func(fragShader);
+   glDeleteShader_func(vertShader);
+   glDeleteProgram_func(program);
+   glutDestroyWindow(win);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+  (void) x;
+  (void) y;
+
+   switch(key) {
+   case 'z':
+      zRot -= 1.0;
+      break;
+   case 'Z':
+      zRot += 1.0;
+      break;
+   case 27:
+      CleanUp();
+      exit(0);
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+   const GLfloat step = 3.0f;
+
+  (void) x;
+  (void) y;
+
+   switch(key) {
+   case GLUT_KEY_UP:
+      xRot -= step;
+      break;
+   case GLUT_KEY_DOWN:
+      xRot += step;
+      break;
+   case GLUT_KEY_LEFT:
+      yRot -= step;
+      break;
+   case GLUT_KEY_RIGHT:
+      yRot += step;
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+
+static void
+LoadAndCompileShader(GLuint shader, const char *text)
+{
+   GLint stat;
+
+   glShaderSource_func(shader, 1, (const GLchar **) &text, NULL);
+
+   glCompileShader_func(shader);
+
+   glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat);
+   if (!stat) {
+      GLchar log[1000];
+      GLsizei len;
+      glGetShaderInfoLog_func(shader, 1000, &len, log);
+      fprintf(stderr, "brick: problem compiling shader: %s\n", log);
+      exit(1);
+   }
+   else {
+      printf("Shader compiled OK\n");
+   }
+}
+
+
+/**
+ * Read a shader from a file.
+ */
+static void
+ReadShader(GLuint shader, const char *filename)
+{
+   const int max = 100*1000;
+   int n;
+   char *buffer = (char*) malloc(max);
+   FILE *f = fopen(filename, "r");
+   if (!f) {
+      fprintf(stderr, "brick: Unable to open shader file %s\n", filename);
+      exit(1);
+   }
+
+   n = fread(buffer, 1, max, f);
+   printf("brick: read %d bytes from shader file %s\n", n, filename);
+   if (n > 0) {
+      buffer[n] = 0;
+      LoadAndCompileShader(shader, buffer);
+   }
+
+   fclose(f);
+   free(buffer);
+}
+
+
+static void
+CheckLink(GLuint prog)
+{
+   GLint stat;
+   glGetProgramiv_func(prog, GL_LINK_STATUS, &stat);
+   if (!stat) {
+      GLchar log[1000];
+      GLsizei len;
+      glGetProgramInfoLog_func(prog, 1000, &len, log);
+      fprintf(stderr, "Linker error:\n%s\n", log);
+   }
+   else {
+      fprintf(stderr, "Link success!\n");
+   }
+}
+
+
+static void
+Init(void)
+{
+   const char *version;
+   GLint i;
+
+   version = (const char *) glGetString(GL_VERSION);
+   if (version[0] != '2' || version[1] != '.') {
+      printf("Warning: this program expects OpenGL 2.0\n");
+      /*exit(1);*/
+   }
+
+   GetExtensionFuncs();
+
+   vertShader = glCreateShader_func(GL_VERTEX_SHADER);
+   ReadShader(vertShader, VertProgFile);
+
+   fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
+   ReadShader(fragShader, FragProgFile);
+
+   program = glCreateProgram_func();
+   glAttachShader_func(program, fragShader);
+   glAttachShader_func(program, vertShader);
+   glLinkProgram_func(program);
+   CheckLink(program);
+   glUseProgram_func(program);
+
+   for (i = 0; Uniforms[i].name; i++) {
+      Uniforms[i].location
+         = glGetUniformLocation_func(program, Uniforms[i].name);
+      printf("Uniform %s location: %d\n", Uniforms[i].name,
+             Uniforms[i].location);
+      switch (Uniforms[i].size) {
+      case 1:
+         glUniform1fv_func(Uniforms[i].location, 1, Uniforms[i].value);
+         break;
+      case 2:
+         glUniform2fv_func(Uniforms[i].location, 1, Uniforms[i].value);
+         break;
+      case 3:
+         glUniform3fv_func(Uniforms[i].location, 1, Uniforms[i].value);
+         break;
+      case 4:
+         glUniform4fv_func(Uniforms[i].location, 1, Uniforms[i].value);
+         break;
+      default:
+         abort();
+      }
+   }
+
+   assert(glGetError() == 0);
+
+   glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
+
+   printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
+
+   assert(glIsProgram_func(program));
+   assert(glIsShader_func(fragShader));
+   assert(glIsShader_func(vertShader));
+
+   glColor3f(1, 0, 0);
+}
+
+
+static void
+ParseOptions(int argc, char *argv[])
+{
+   int i;
+   for (i = 1; i < argc; i++) {
+      if (strcmp(argv[i], "-fs") == 0) {
+         FragProgFile = argv[i+1];
+      }
+      else if (strcmp(argv[i], "-vs") == 0) {
+         VertProgFile = argv[i+1];
+      }
+   }
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition( 0, 0);
+   glutInitWindowSize(400, 400);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutSpecialFunc(SpecialKey);
+   glutDisplayFunc(Redisplay);
+   ParseOptions(argc, argv);
+   Init();
+   glutMainLoop();
+   return 0;
+}
+