--- /dev/null
+/**
+ * Test linking of multiple compilation units.
+ * Brian Paul
+ * 28 March 2009
+ */
+
+#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 GLfloat diffuse[4] = { 0.5f, 1.0f, 0.5f, 1.0f };
+static GLfloat specular[4] = { 0.8f, 0.8f, 0.8f, 1.0f };
+static GLfloat lightPos[4] = { 0.0f, 10.0f, 20.0f, 0.0f };
+static GLfloat delta = 1.0f;
+
+static GLuint VertShader1;
+static GLuint VertShader2;
+static GLuint FragShader1;
+static GLuint FragShader2;
+static GLuint Program;
+
+static GLint uDiffuse;
+static GLint uSpecular;
+static GLint uTexture;
+
+static GLint Win = 0;
+static GLboolean anim = GL_TRUE;
+
+
+
+static const char *FragShaderSource1 =
+ "float compute_dotprod(const vec3 normal) \n"
+ "{ \n"
+ " float dotProd = max(dot(gl_LightSource[0].position.xyz, \n"
+ " normalize(normal)), 0.0); \n"
+ " return dotProd; \n"
+ "} \n";
+
+static const char *FragShaderSource2 =
+ "uniform vec4 diffuse;\n"
+ "uniform vec4 specular;\n"
+ "varying vec3 normal;\n"
+ "\n"
+ "// external function \n"
+ "float compute_dotprod(const vec3 normal); \n"
+ "\n"
+ "void main() \n"
+ "{ \n"
+ " float dotProd = compute_dotprod(normal); \n"
+ " gl_FragColor = diffuse * dotProd + specular * pow(dotProd, 20.0); \n"
+ "} \n";
+
+
+static const char *VertShaderSource1 =
+ "vec3 compute_normal() \n"
+ "{ \n"
+ " return gl_NormalMatrix * gl_Normal; \n"
+ "} \n";
+
+static const char *VertShaderSource2 =
+ "varying vec3 normal;\n"
+ "\n"
+ "// external function \n"
+ "vec3 compute_normal(); \n"
+ "\n"
+ "void main() \n"
+ "{ \n"
+ " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; \n"
+ " normal = compute_normal(); \n"
+ "} \n";
+
+
+static void
+normalize(GLfloat *dst, const GLfloat *src)
+{
+ GLfloat len = sqrt(src[0] * src[0] + src[1] * src[1] + src[2] * src[2]);
+ dst[0] = src[0] / len;
+ dst[1] = src[1] / len;
+ dst[2] = src[2] / len;
+ dst[3] = src[3];
+}
+
+
+static void
+Redisplay(void)
+{
+ GLfloat vec[4];
+
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ /* update light position */
+ normalize(vec, lightPos);
+ glLightfv(GL_LIGHT0, GL_POSITION, vec);
+
+ glutSolidSphere(2.0, 10, 5);
+
+ glutSwapBuffers();
+}
+
+
+static void
+Idle(void)
+{
+ lightPos[0] += delta;
+ if (lightPos[0] > 25.0f || lightPos[0] < -25.0f)
+ delta = -delta;
+ 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(VertShader1);
+ glDeleteShader_func(VertShader2);
+ glDeleteShader_func(FragShader1);
+ glDeleteShader_func(FragShader2);
+ 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 'x':
+ lightPos[0] -= 1.0f;
+ break;
+ case 'X':
+ lightPos[0] += 1.0f;
+ break;
+ case 27:
+ CleanUp();
+ exit(0);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+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)
+{
+ if (!ShadersSupported())
+ exit(1);
+
+ GetExtensionFuncs();
+
+ printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
+
+ VertShader1 = CompileShaderText(GL_VERTEX_SHADER, VertShaderSource1);
+ VertShader2 = CompileShaderText(GL_VERTEX_SHADER, VertShaderSource2);
+ FragShader1 = CompileShaderText(GL_FRAGMENT_SHADER, FragShaderSource1);
+ FragShader2 = CompileShaderText(GL_FRAGMENT_SHADER, FragShaderSource2);
+
+ Program = glCreateProgram_func();
+ glAttachShader_func(Program, VertShader1);
+ glAttachShader_func(Program, VertShader2);
+ glAttachShader_func(Program, FragShader1);
+ glAttachShader_func(Program, FragShader2);
+
+ glLinkProgram_func(Program);
+
+ CheckLink(Program);
+
+ glUseProgram_func(Program);
+
+ uDiffuse = glGetUniformLocation_func(Program, "diffuse");
+ uSpecular = glGetUniformLocation_func(Program, "specular");
+ uTexture = glGetUniformLocation_func(Program, "texture");
+ printf("DiffusePos %d SpecularPos %d TexturePos %d\n",
+ uDiffuse, uSpecular, uTexture);
+
+ glUniform4fv_func(uDiffuse, 1, diffuse);
+ glUniform4fv_func(uSpecular, 1, specular);
+
+ glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
+ glEnable(GL_DEPTH_TEST);
+
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, diffuse);
+ glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, specular);
+ glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 10.0f);
+
+ assert(glIsProgram_func(Program));
+ assert(glIsShader_func(VertShader1));
+ assert(glIsShader_func(VertShader2));
+ assert(glIsShader_func(FragShader1));
+ assert(glIsShader_func(FragShader2));
+
+ glColor3f(1, 0, 0);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ glutInit(&argc, argv);
+ glutInitWindowPosition( 0, 0);
+ glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+ Win = glutCreateWindow(argv[0]);
+ glutReshapeFunc(Reshape);
+ glutKeyboardFunc(Key);
+ glutDisplayFunc(Redisplay);
+ if (anim)
+ glutIdleFunc(Idle);
+ Init();
+ glutMainLoop();
+ return 0;
+}
+
+