Merge branch 'master' of git+ssh://joukj@git.freedesktop.org/git/mesa/mesa

4 files changed, 1009 insertions, 3 deletions

diff --git a/progs/glsl/Makefile b/progs/glsl/Makefile
index 37fa312c30..8b44239b43 100644
--- a/progs/glsl/Makefile
+++ b/progs/glsl/Makefile
@@ -8,13 +8,16 @@ INCDIR = $(TOP)/include
 LIB_DEP = $(TOP)/$(LIB_DIR)/$(GL_LIB_NAME) $(TOP)/$(LIB_DIR)/$(GLU_LIB_NAME) $(TOP)/$(LIB_DIR)/$(GLUT_LIB_NAME)
 
 PROGS = \
+	bitmap \
 	brick \
 	bump \
 	deriv \
 	mandelbrot \
 	noise \
+	points \
+	texdemo1 \
 	toyball \
-	texdemo1
+	trirast
 
 
 ##### RULES #####
@@ -25,7 +28,7 @@ PROGS = \
 
 # make executable from .c file:
 .c: $(LIB_DEP)
-	$(CC) -I$(INCDIR) $(CFLAGS) $< $(APP_LIB_DEPS) -o $@
+	$(CC) -I$(INCDIR) $(CFLAGS) $(LDFLAGS) $< $(APP_LIB_DEPS) -o $@
 
 
 ##### TARGETS #####
@@ -48,16 +51,20 @@ readtex.h: $(TOP)/progs/util/readtex.h
 readtex.o: readtex.c readtex.h
 	$(CC) -c -I$(INCDIR) $(CFLAGS) readtex.c
 
+bitmap.c: extfuncs.h
+
 brick.c: extfuncs.h
 
 bump.c: extfuncs.h
 
 mandelbrot.c: extfuncs.h
 
+points.c: extfuncs.h
+
 toyball.c: extfuncs.h
 
 texdemo1: texdemo1.o readtex.o
-	$(CC) -I$(INCDIR) $(CFLAGS) texdemo1.o readtex.o $(APP_LIB_DEPS) -o $@
+	$(CC) -I$(INCDIR) $(CFLAGS) $(LDFLAGS) texdemo1.o readtex.o $(APP_LIB_DEPS) -o $@
 
 texdemo1.o: texdemo1.c readtex.h extfuncs.h
 	$(CC) -c -I$(INCDIR) $(CFLAGS) texdemo1.c
diff --git a/progs/glsl/bitmap.c b/progs/glsl/bitmap.c
new file mode 100644
index 0000000000..4b62686cbf
--- /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;
+}
+
+
diff --git a/progs/glsl/points.c b/progs/glsl/points.c
new file mode 100644
index 0000000000..85115de504
--- /dev/null
+++ b/progs/glsl/points.c
@@ -0,0 +1,305 @@
+/**
+ * Implement smooth (AA) points with shaders.
+ * A simple variation could be used for sprite points.
+ * Brian Paul
+ * 29 July 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 = 200;
+static GLfloat Xpos = 0.0f, Ypos = 0.0f;
+static GLint uViewportInv;
+static GLboolean Smooth = GL_TRUE, Blend = GL_TRUE;
+
+
+/**
+ * Issue vertices for a "shader point".
+ * The position is duplicated, only texcoords (or other vertex attrib) change.
+ * The vertex program will compute the "real" quad corners.
+ */
+static void
+PointVertex3f(GLfloat x, GLfloat y, GLfloat z)
+{
+   glTexCoord2f(-1, -1);
+   glVertex3f(x, y, z);
+
+   glTexCoord2f( 1, -1);
+   glVertex3f(x, y, z);
+
+   glTexCoord2f( 1,  1);
+   glVertex3f(x, y, z);
+
+   glTexCoord2f(-1,  1);
+   glVertex3f(x, y, z);
+}
+
+
+static void
+DrawPoints(GLboolean shaderPoints)
+{
+   int i;
+   for (i = 0; i < 9; i++) {
+      GLfloat x = i - 4, y = 0, z = 0;
+      /* note: can't call glPointSize inside Begin/End :( */
+      glPointSize( 2 + i * 5 );
+      if (shaderPoints) {
+         glBegin(GL_QUADS);
+         PointVertex3f(x, y, z);
+         glEnd();
+      }
+      else {
+         glBegin(GL_POINTS);
+         glVertex3f(x, y, z);
+         glEnd();
+      }
+   }
+}
+
+
+/**
+ * Top row of points rendered convetionally,
+ * bottom row rendered with shaders.
+ */
+static void
+Redisplay(void)
+{
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   if (Smooth)
+      glEnable(GL_POINT_SMOOTH);
+   else
+      glDisable(GL_POINT_SMOOTH);
+
+   if (Blend)
+      glEnable(GL_BLEND);
+   else
+      glDisable(GL_BLEND);
+
+   glPushMatrix();
+   glTranslatef(Xpos, Ypos, 0);
+
+   /*
+    * regular points
+    */
+   glPushMatrix();
+   glTranslatef(0, 1.2, 0);
+   glUseProgram_func(0);
+   DrawPoints(GL_FALSE);
+   glPopMatrix();
+
+   /*
+    * shader points
+    */
+   glPushMatrix();
+   glTranslatef(0, -1.2, 0);
+   glUseProgram_func(Program);
+   if (uViewportInv != -1) {
+      glUniform2f_func(uViewportInv, 1.0 / WinWidth, 1.0 / WinHeight);
+   }
+   DrawPoints(GL_TRUE);
+   glPopMatrix();
+
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+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, 4.0, 30.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0f, 0.0f, -20.0f);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+  (void) x;
+  (void) y;
+
+   switch(key) {
+   case 'b':
+      Blend = !Blend;
+      break;
+   case 's':
+      Smooth = !Smooth;
+      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 = 1/100.0;
+   switch(key) {
+   case GLUT_KEY_UP:
+      Ypos += step;
+      break;
+   case GLUT_KEY_DOWN:
+      Ypos -= step;
+      break;
+   case GLUT_KEY_LEFT:
+      Xpos -= step;
+      break;
+   case GLUT_KEY_RIGHT:
+      Xpos += 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, "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: compute distance of fragment from center of point
+    * (we're using texcoords but another varying could be used).
+    *   if dist > 1, discard (coverage==0)
+    *   if dist < k, coverage = 1
+    *   else, coverage = func(dist)
+    * Note: length() uses sqrt() and may be expensive.  The distance could
+    * be squared instead (with adjustments to the threshold (k) test)
+    */
+   static const char *fragShaderText =
+      "void main() {\n"
+      "   float cover; \n"
+      "   float k = 2.0 / gl_Point.size; \n"
+      "   float d = length(gl_TexCoord[0].xy); \n"
+      "   if (d >= 1.0) \n"
+      "      discard; \n"
+      "   if (d < 1.0 - k) \n"
+      "      cover = 1.0; \n"
+      "   else \n"
+      "      cover = (1.0 - d) * 0.5 * gl_Point.size; \n"
+      "   gl_FragColor.rgb = gl_Color.rgb; \n"
+      "   gl_FragColor.a = cover; \n"
+      "}\n";
+   /* Vertex shader: compute new vertex position based on incoming vertex pos,
+    * texcoords, point size, and inverse viewport scale factor.
+    * Note: should compute point size attenuation here too.
+    */
+   static const char *vertShaderText =
+      "uniform vec2 viewportInv; \n"
+      "void main() {\n"
+      "   vec4 pos = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+      "   gl_Position.xy = pos.xy + gl_MultiTexCoord0.xy * viewportInv \n"
+      "                    * gl_Point.size * pos.w; \n"
+      "   gl_Position.zw = pos.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);
+
+   uViewportInv = glGetUniformLocation_func(Program, "viewportInv");
+
+   glUseProgram_func(0);
+
+   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+}
+
+
+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);
+   Init();
+   glutMainLoop();
+   return 0;
+}
+
+
diff --git a/progs/glsl/trirast.c b/progs/glsl/trirast.c
new file mode 100644
index 0000000000..e4325deb1f
--- /dev/null
+++ b/progs/glsl/trirast.c
@@ -0,0 +1,326 @@
+/**
+ * Demonstration of doing triangle rasterization with a fragment program.
+ * Basic idea:
+ *   1. Draw screen-aligned quad / bounding box around the triangle verts.
+ *   2. For each pixel in the quad, determine if pixel is inside/outside
+ *      the triangle edges.
+ *
+ * Brian Paul
+ * 1 Aug 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 GLint WinWidth = 300, WinHeight = 300;
+static char *FragProgFile = NULL;
+static char *VertProgFile = NULL;
+static GLuint fragShader;
+static GLuint vertShader;
+static GLuint program;
+static GLint win = 0;
+static GLboolean anim = GL_TRUE;
+static GLfloat Zrot = 0.0f;
+static GLint uv0, uv1, uv2;
+
+
+static const GLfloat TriVerts[3][2] = {
+   { 50,  50 },
+   { 250, 50 },
+   { 150, 250 }
+};
+
+
+static void
+RotateVerts(GLfloat a,
+            GLuint n, const GLfloat vertsIn[][2], GLfloat vertsOut[][2])
+{
+   GLuint i;
+   GLfloat cx = WinWidth / 2, cy = WinHeight / 2;
+   for (i = 0; i < n; i++) {
+      float x = vertsIn[i][0] - cx;
+      float y = vertsIn[i][1] - cy;
+      
+      vertsOut[i][0] =  x * cos(a) + y * sin(a)  + cx;
+      vertsOut[i][1] = -x * sin(a) + y * cos(a)  + cy;
+   }
+}
+
+static void
+ComputeBounds(GLuint n, GLfloat vertsIn[][2],
+              GLfloat *xmin, GLfloat *ymin,
+              GLfloat *xmax, GLfloat *ymax)
+{
+   GLuint i;
+   *xmin = *xmax = vertsIn[0][0];
+   *ymin = *ymax = vertsIn[0][1];
+   for (i = 1; i < n; i++) {
+      if (vertsIn[i][0] < *xmin)
+         *xmin = vertsIn[i][0];
+      else if (vertsIn[i][0] > *xmax)
+         *xmax = vertsIn[i][0];
+      if (vertsIn[i][1] < *ymin)
+         *ymin = vertsIn[i][1];
+      else if (vertsIn[i][1] > *ymax)
+         *ymax = vertsIn[i][1];
+   }
+}
+
+
+static void
+Redisplay(void)
+{
+   GLfloat v[3][2], xmin, ymin, xmax, ymax;
+
+   RotateVerts(Zrot, 3, TriVerts, v);
+   ComputeBounds(3, v, &xmin, &ymin, &xmax, &ymax);
+
+   glUniform2fv_func(uv0, 1, v[0]);
+   glUniform2fv_func(uv1, 1, v[1]);
+   glUniform2fv_func(uv2, 1, v[2]);
+
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   glPushMatrix();
+   glBegin(GL_POLYGON);
+   glVertex2f(xmin, ymin);
+   glVertex2f(xmax, ymin);
+   glVertex2f(xmax, ymax);
+   glVertex2f(xmin, ymax);
+   glEnd();
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+Idle(void)
+{
+   Zrot = glutGet(GLUT_ELAPSED_TIME) * 0.0005;
+   glutPostRedisplay();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glOrtho(0, width, 0, height, -1, 1);
+
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+}
+
+
+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 ' ':
+   case 'a':
+      anim = !anim;
+      if (anim)
+         glutIdleFunc(Idle);
+      else
+         glutIdleFunc(NULL);
+      break;
+   case 27:
+      CleanUp();
+      exit(0);
+      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, "fslight: problem compiling shader:\n%s\n", log);
+      exit(1);
+   }
+}
+
+
+/**
+ * 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, "fslight: Unable to open shader file %s\n", filename);
+      exit(1);
+   }
+
+   n = fread(buffer, 1, max, f);
+   printf("fslight: 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);
+   }
+}
+
+
+static void
+Init(void)
+{
+   static const char *fragShaderText =
+      "uniform vec2 v0, v1, v2; \n"
+      "float crs(const vec2 u, const vec2 v) \n"
+      "{ \n"
+      "   return u.x * v.y - u.y * v.x; \n"
+      "} \n"
+      "\n"
+      "void main() {\n"
+      "   vec2 p = gl_FragCoord.xy; \n"
+      "   if (crs(v1 - v0, p - v0) >= 0 && \n"
+      "       crs(v2 - v1, p - v1) >= 0 && \n"
+      "       crs(v0 - v2, p - v2) >= 0) \n"
+      "      gl_FragColor = vec4(1.0); \n"
+      "   else \n"
+      "      gl_FragColor = vec4(0.5); \n"
+      "}\n";
+   static const char *vertShaderText =
+      "void main() {\n"
+      "   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\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);
+   }
+
+   GetExtensionFuncs();
+
+   fragShader = glCreateShader_func(GL_FRAGMENT_SHADER);
+   if (FragProgFile)
+      ReadShader(fragShader, FragProgFile);
+   else
+      LoadAndCompileShader(fragShader, fragShaderText);
+
+   vertShader = glCreateShader_func(GL_VERTEX_SHADER);
+   if (VertProgFile)
+      ReadShader(vertShader, VertProgFile);
+   else
+      LoadAndCompileShader(vertShader, vertShaderText);
+
+   program = glCreateProgram_func();
+   glAttachShader_func(program, fragShader);
+   glAttachShader_func(program, vertShader);
+   glLinkProgram_func(program);
+   CheckLink(program);
+   glUseProgram_func(program);
+
+   uv0 = glGetUniformLocation_func(program, "v0");
+   uv1 = glGetUniformLocation_func(program, "v1");
+   uv2 = glGetUniformLocation_func(program, "v2");
+   printf("Uniforms: %d %d %d\n", uv0, uv1, uv2);
+
+   /*assert(glGetError() == 0);*/
+
+   glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
+   glEnable(GL_DEPTH_TEST);
+
+   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(WinWidth, WinHeight);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutDisplayFunc(Redisplay);
+   if (anim)
+      glutIdleFunc(Idle);
+   ParseOptions(argc, argv);
+   Init();
+   glutMainLoop();
+   return 0;
+}