New test of the dFdx(), dFdy() functions.

1 files changed, 321 insertions, 0 deletions

diff --git a/progs/glsl/deriv.c b/progs/glsl/deriv.c
new file mode 100644
index 00000000000..63beef1c941
--- /dev/null
+++ b/progs/glsl/deriv.c
@@ -0,0 +1,321 @@
+/**
+ * Test OpenGL 2.0 dx/dy functions for texcoords.
+ * Brian Paul
+ * 2 May 2007
+ *
+ * NOTE: resize the window to observe how the partial derivatives of
+ * the texcoords change.
+ */
+
+
+#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 = NULL;
+static char *VertProgFile = NULL;
+static GLuint fragShader;
+static GLuint vertShader;
+static GLuint program;
+static GLuint SphereList, RectList, CurList;
+static GLint win = 0;
+static GLboolean anim = GL_TRUE;
+static GLfloat xRot = 0.0f, yRot = 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);
+   glCallList(CurList);
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+Idle(void)
+{
+   yRot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
+   glutPostRedisplay();
+}
+
+
+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, -15.0f);
+}
+
+
+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 ' ':
+   case 'a':
+      anim = !anim;
+      if (anim)
+         glutIdleFunc(Idle);
+      else
+         glutIdleFunc(NULL);
+      break;
+   case 'o':
+      if (CurList == SphereList)
+         CurList = RectList;
+      else
+         CurList = SphereList;
+      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
+MakeSphere(void)
+{
+   GLUquadricObj *obj = gluNewQuadric();
+   SphereList = glGenLists(1);
+   gluQuadricTexture(obj, GL_TRUE);
+   glNewList(SphereList, GL_COMPILE);
+   gluSphere(obj, 2.0f, 30, 15);
+   glEndList();
+}
+
+
+static void
+MakeRect(void)
+{
+   RectList = glGenLists(1);
+   glNewList(RectList, GL_COMPILE);
+   glNormal3f(0, 0, 1);
+   glBegin(GL_POLYGON);
+   glTexCoord2f(0, 0);   glVertex2f(-2, -2);
+   glTexCoord2f(1, 0);   glVertex2f( 2, -2);
+   glTexCoord2f(1, 1);   glVertex2f( 2,  2);
+   glTexCoord2f(0, 1);   glVertex2f(-2,  2);
+   glEnd();
+   glEndList();
+}
+
+
+
+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 =
+      "void main() {\n"
+      "   gl_FragColor = abs(dFdy(gl_TexCoord[0])) * 50.0;\n"
+      "  // gl_FragColor = gl_TexCoord[0];\n"
+      "}\n";
+   static const char *vertShaderText =
+      "varying vec3 normal;\n"
+      "void main() {\n"
+      "   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
+      "   gl_TexCoord[0] = gl_MultiTexCoord0;\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);
+
+   /*assert(glGetError() == 0);*/
+
+   glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
+   glEnable(GL_DEPTH_TEST);
+
+   MakeSphere();
+   MakeRect();
+
+   CurList = SphereList;
+
+   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(200, 200);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutSpecialFunc(SpecialKey);
+   glutDisplayFunc(Redisplay);
+   if (anim)
+      glutIdleFunc(Idle);
+   ParseOptions(argc, argv);
+   Init();
+   glutMainLoop();
+   return 0;
+}