1 files changed, 280 insertions, 0 deletions
diff --git a/progs/glsl/skinning.c b/progs/glsl/skinning.c
new file mode 100644
index 000000000..8a65d0667
--- /dev/null
+++ b/progs/glsl/skinning.c
@@ -0,0 +1,280 @@
+/**
+ * Vertex "skinning" example.
+ * The idea is there are multiple modeling matrices applied to every
+ * vertex.  Weighting values in [0,1] control the influence of each
+ * matrix on each vertex.
+ *
+ * 4 Nov 2008
+ */
+
+#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"
+#include "shaderutil.h"
+
+
+static char *FragProgFile = "skinning.frag";
+static char *VertProgFile = "skinning.vert";
+
+/* program/shader objects */
+static GLuint fragShader;
+static GLuint vertShader;
+static GLuint program;
+
+
+static GLint win = 0;
+static GLboolean Anim = GL_TRUE;
+static GLboolean WireFrame = GL_TRUE;
+static GLfloat xRot = 0.0f, yRot = 90.0f, zRot = 0.0f;
+
+#define NUM_MATS 2
+
+static GLfloat Matrices[NUM_MATS][16];
+static GLint uMat0, uMat1;
+static GLint WeightAttr;
+
+
+static void
+Idle(void)
+{
+   yRot = 90 + glutGet(GLUT_ELAPSED_TIME) * 0.005;
+   glutPostRedisplay();
+}
+
+
+static void
+Cylinder(GLfloat length, GLfloat radius, GLint slices, GLint stacks)
+{
+   float dw = 1.0 / (stacks - 1);
+   float dz = length / stacks;
+   int i, j;
+
+   for (j = 0; j < stacks; j++) {
+      float w0 = j * dw;
+      float z0 = j * dz;
+
+      glBegin(GL_TRIANGLE_STRIP);
+      for (i = 0; i < slices; i++) {
+         float a = (float) i / (slices - 1) * M_PI * 2.0;
+         float x = radius * cos(a);
+         float y = radius * sin(a);
+         glVertexAttrib1f_func(WeightAttr, w0);
+         glNormal3f(x, y, 0.0);
+         glVertex3f(x, y, z0);
+
+         glVertexAttrib1f_func(WeightAttr, w0 + dw);
+         glNormal3f(x, y, 0.0);
+         glVertex3f(x, y, z0 + dz);
+      }
+      glEnd();
+   }
+}
+
+
+/**
+ * Update/animate the two matrices.  One rotates, the other scales.
+ */
+static void
+UpdateMatrices(void)
+{
+   GLfloat t = glutGet(GLUT_ELAPSED_TIME) * 0.0025;
+   GLfloat scale = 0.5 * (1.1 + sin(0.5 * t));
+   GLfloat rot = cos(t) * 90.0;
+
+   glPushMatrix();
+   glLoadIdentity();
+   glScalef(1.0, scale, 1.0);
+   glGetFloatv(GL_MODELVIEW_MATRIX, Matrices[0]);
+   glPopMatrix();
+
+   glPushMatrix();
+   glLoadIdentity();
+   glRotatef(rot, 0, 0, 1);
+   glGetFloatv(GL_MODELVIEW_MATRIX, Matrices[1]);
+   glPopMatrix();
+}
+
+
+static void
+Redisplay(void)
+{
+   UpdateMatrices();
+
+   glUniformMatrix4fv_func(uMat0, 1, GL_FALSE, Matrices[0]);
+   glUniformMatrix4fv_func(uMat1, 1, GL_FALSE, Matrices[1]);
+
+   if (WireFrame)
+      glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+   else
+      glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+
+   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);
+
+   glPushMatrix();
+   glTranslatef(0, 0, -2.5);
+   Cylinder(5.0, 1.0, 10, 20);
+   glPopMatrix();
+
+   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, -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)
+{
+   const GLfloat step = 2.0;
+  (void) x;
+  (void) y;
+
+   switch(key) {
+   case 'a':
+      Anim = !Anim;
+      if (Anim)
+         glutIdleFunc(Idle);
+      else
+         glutIdleFunc(NULL);
+      break;
+   case 'w':
+      WireFrame = !WireFrame;
+      break;
+   case 'z':
+      zRot += step;
+      break;
+   case 'Z':
+      zRot -= step;
+      break;
+   case 27:
+      CleanUp();
+      exit(0);
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+   const GLfloat step = 2.0;
+
+  (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
+Init(void)
+{
+   if (!ShadersSupported())
+      exit(1);
+
+   GetExtensionFuncs();
+
+   vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
+   fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
+   program = LinkShaders(vertShader, fragShader);
+
+   glUseProgram_func(program);
+
+   uMat0 = glGetUniformLocation_func(program, "mat0");
+   uMat1 = glGetUniformLocation_func(program, "mat1");
+
+   WeightAttr = glGetAttribLocation_func(program, "weight");
+
+   assert(glGetError() == 0);
+
+   glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
+
+   glEnable(GL_DEPTH_TEST);
+
+   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);
+   glutInitWindowSize(500, 500);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutSpecialFunc(SpecialKey);
+   glutDisplayFunc(Redisplay);
+   ParseOptions(argc, argv);
+   Init();
+   if (Anim)
+      glutIdleFunc(Idle);
+   glutMainLoop();
+   return 0;
+}
+