Added shader points and shader bitmap demos

1 files changed, 368 insertions, 0 deletions

diff --git a/progs/glsl/bitmap.c b/progs/glsl/bitmap.c
new file mode 100644
index 00000000000..4b62686cbff
--- /dev/null
+++ b/progs/glsl/bitmap.c
@@ -0,0 +1,368 @@
+/**
+ * Implement glRasterPos + glBitmap with textures + shaders.
+ * Brian Paul
+ * 14 May 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 GLuint FragShader;
+static GLuint VertShader;
+static GLuint Program;
+
+static GLint Win = 0;
+static GLint WinWidth = 500, WinHeight = 500;
+static GLboolean Anim = GL_TRUE;
+static GLboolean Bitmap = GL_FALSE;
+static GLfloat Xrot = 20.0f, Yrot = 70.0f;
+static GLint uTex, uScale;
+static GLuint Textures[2];
+
+#define TEX_WIDTH 16
+#define TEX_HEIGHT 8
+
+
+static void
+BitmapText(const char *s)
+{
+   while (*s) {
+      glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+      s++;
+   }
+}
+
+
+static void
+Redisplay(void)
+{
+   static const GLfloat px[3] = { 1.2, 0, 0};
+   static const GLfloat nx[3] = {-1.2, 0, 0};
+
+   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);
+
+   glEnable(GL_LIGHTING);
+
+   glPushMatrix();
+   glScalef(0.5, 0.5, 0.5);
+   glutSolidDodecahedron();
+   glPopMatrix();
+
+   glDisable(GL_LIGHTING);
+
+   glColor3f(0, 1, 0);
+   glBegin(GL_LINES);
+   glVertex3f(-1, 0, 0);
+   glVertex3f( 1, 0, 0);
+   glEnd();
+
+   glColor3f(1, 1, 0);
+
+   if (Bitmap) {
+      glRasterPos3fv(px);
+      BitmapText("+X");
+      glRasterPos3fv(nx);
+      BitmapText("-X");
+   }
+   else {
+      glUseProgram_func(Program);
+
+      /* vertex positions (deltas) depend on texture size and window size */
+      if (uScale != -1) {
+         glUniform2f_func(uScale,
+                          2.0 * TEX_WIDTH / WinWidth,
+                          2.0 * TEX_HEIGHT / WinHeight);
+      }
+
+      /* draw +X */
+      glBindTexture(GL_TEXTURE_2D, Textures[0]);
+      glBegin(GL_QUADS);
+      glTexCoord2f(0, 0);  glVertex3fv(px);
+      glTexCoord2f(1, 0);  glVertex3fv(px);
+      glTexCoord2f(1, 1);  glVertex3fv(px);
+      glTexCoord2f(0, 1);  glVertex3fv(px);
+      glEnd();
+
+      /* draw -X */
+      glBindTexture(GL_TEXTURE_2D, Textures[1]);
+      glBegin(GL_QUADS);
+      glTexCoord2f(0, 0);  glVertex3fv(nx);
+      glTexCoord2f(1, 0);  glVertex3fv(nx);
+      glTexCoord2f(1, 1);  glVertex3fv(nx);
+      glTexCoord2f(0, 1);  glVertex3fv(nx);
+      glEnd();
+
+      glUseProgram_func(0);
+   }
+
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+Idle(void)
+{
+   Yrot = glutGet(GLUT_ELAPSED_TIME) * 0.01;
+   glutPostRedisplay();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   WinWidth = width;
+   WinHeight = 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, -10.0f);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+  (void) x;
+  (void) y;
+
+   switch(key) {
+   case ' ':
+   case 'a':
+      Anim = !Anim;
+      if (Anim)
+         glutIdleFunc(Idle);
+      else
+         glutIdleFunc(NULL);
+      break;
+   case 'b':
+      Bitmap = !Bitmap;
+      if (Bitmap)
+         printf("Using glBitmap\n");
+      else
+         printf("Using billboard texture\n");
+      break;
+   case 27:
+      glDeleteShader_func(FragShader);
+      glDeleteShader_func(VertShader);
+      glDeleteProgram_func(Program);
+      glutDestroyWindow(Win);
+      exit(0);
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+   const GLfloat step = 0.125f;
+   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;
+   }
+   /*printf("Xrot: %f  Yrot: %f\n", Xrot, Yrot);*/
+   glutPostRedisplay();
+}
+
+
+static void
+MakeTexImage(const char *p, GLuint texobj)
+{
+   GLubyte image[TEX_HEIGHT][TEX_WIDTH];
+   GLuint i, j, k;
+
+   for (i = 0; i < TEX_HEIGHT; i++) {
+      for (j = 0; j < TEX_WIDTH; j++) {
+         k = i * TEX_WIDTH + j;
+         if (p[k] == ' ') {
+            image[i][j] = 0;
+         }
+         else {
+            image[i][j] = 255;
+         }
+      }
+   }
+
+   glBindTexture(GL_TEXTURE_2D, texobj);
+   glTexImage2D(GL_TEXTURE_2D, 0, GL_INTENSITY, TEX_WIDTH, TEX_HEIGHT, 0,
+                GL_RED, GL_UNSIGNED_BYTE, image);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+}
+
+
+static void
+MakeBitmapTextures(void)
+{
+   const char *px =
+      "        X     X "
+      "   X     X   X  "
+      "   X      X X   "
+      " XXXXX     X    "
+      "   X      X X   "
+      "   X     X   X  "
+      "        X     X "
+      "        X     X ";
+   const char *nx =
+      "        X     X "
+      "         X   X  "
+      "          X X   "
+      " XXXXX     X    "
+      "          X X   "
+      "         X   X  "
+      "        X     X "
+      "        X     X ";
+   glGenTextures(2, Textures);
+   MakeTexImage(px, Textures[0]);
+   MakeTexImage(nx, Textures[1]);
+}
+
+
+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, "fslight: problem compiling shader:\n%s\n", log);
+      exit(1);
+   }
+}
+
+
+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);
+   }
+}
+
+
+static void
+Init(void)
+{
+   /* Fragment shader: modulate raster color by texture, discard fragments
+    * with alpha < 1.0
+    */
+   static const char *fragShaderText =
+      "uniform sampler2D tex2d; \n"
+      "void main() {\n"
+      "   vec4 c = texture2D(tex2d, gl_TexCoord[0].xy); \n"
+      "   if (c.w < 1.0) \n"
+      "      discard; \n"
+      "   gl_FragColor = c * gl_Color; \n"
+      "}\n";
+   /* Vertex shader: compute new vertex position based on incoming vertex pos,
+    * texcoords and special scale factor.
+    */
+   static const char *vertShaderText =
+      "uniform vec2 scale; \n"
+      "void main() {\n"
+      "   vec4 p = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+      "   gl_Position.xy = p.xy + gl_MultiTexCoord0.xy * scale * p.w; \n"
+      "   gl_Position.zw = p.zw; \n"
+      "   gl_TexCoord[0] = gl_MultiTexCoord0; \n"
+      "   gl_FrontColor = gl_Color; \n"
+      "}\n";
+   const char *version;
+
+   version = (const char *) glGetString(GL_VERSION);
+   if (version[0] != '2' || version[1] != '.') {
+      printf("This program requires OpenGL 2.x, found %s\n", version);
+      exit(1);
+   }
+   printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
+
+   GetExtensionFuncs();
+
+   FragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
+   LoadAndCompileShader(FragShader, fragShaderText);
+
+   VertShader = glCreateShader_func(GL_VERTEX_SHADER);
+   LoadAndCompileShader(VertShader, vertShaderText);
+
+   Program = glCreateProgram_func();
+   glAttachShader_func(Program, FragShader);
+   glAttachShader_func(Program, VertShader);
+   glLinkProgram_func(Program);
+   CheckLink(Program);
+   glUseProgram_func(Program);
+
+   uScale = glGetUniformLocation_func(Program, "scale");
+   uTex = glGetUniformLocation_func(Program, "tex2d");
+   if (uTex != -1) {
+      glUniform1i_func(uTex, 0);  /* tex unit 0 */
+   }
+
+   glUseProgram_func(0);
+
+   glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
+   glEnable(GL_DEPTH_TEST);
+   glEnable(GL_NORMALIZE);
+   glEnable(GL_LIGHT0);
+
+   MakeBitmapTextures();
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowSize(WinWidth, WinHeight);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   Win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutSpecialFunc(SpecialKey);
+   glutDisplayFunc(Redisplay);
+   if (Anim)
+      glutIdleFunc(Idle);
+   Init();
+   glutMainLoop();
+   return 0;
+}
+
+