2 * smooth_opengl3.c, based on smooth.c, which is (c) by SGI, see below.
3 * This program demonstrates smooth shading in a way which is fully
4 * OpenGL-3.0-compliant.
5 * A smooth shaded polygon is drawn in a 2-D projection.
9 * Original copyright notice from smooth.c:
11 * License Applicability. Except to the extent portions of this file are
12 * made subject to an alternative license as permitted in the SGI Free
13 * Software License B, Version 1.1 (the "License"), the contents of this
14 * file are subject only to the provisions of the License. You may not use
15 * this file except in compliance with the License. You may obtain a copy
16 * of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
17 * Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
19 * http://oss.sgi.com/projects/FreeB
21 * Note that, as provided in the License, the Software is distributed on an
22 * "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
23 * DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
24 * CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
25 * PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
27 * Original Code. The Original Code is: OpenGL Sample Implementation,
28 * Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
29 * Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
30 * Copyright in any portions created by third parties is as indicated
31 * elsewhere herein. All Rights Reserved.
33 * Additional Notice Provisions: The application programming interfaces
34 * established by SGI in conjunction with the Original Code are The
35 * OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
36 * April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
37 * 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
38 * Window System(R) (Version 1.3), released October 19, 1998. This software
39 * was created using the OpenGL(R) version 1.2.1 Sample Implementation
40 * published by SGI, but has not been independently verified as being
41 * compliant with the OpenGL(R) version 1.2.1 Specification.
45 #include <GL/freeglut.h>
50 /* report GL errors, if any, to stderr */
51 void checkError(const char *functionName)
54 while (( error = glGetError() ) != GL_NO_ERROR) {
55 fprintf (stderr, "GL error 0x%X detected in %s\n", error, functionName);
59 /* extension #defines, types and entries, avoiding a dependency on additional
60 libraries like GLEW or the GL/glext.h header */
61 #ifndef GL_ARRAY_BUFFER
62 #define GL_ARRAY_BUFFER 0x8892
65 #ifndef GL_STATIC_DRAW
66 #define GL_STATIC_DRAW 0x88E4
69 #ifndef GL_FRAGMENT_SHADER
70 #define GL_FRAGMENT_SHADER 0x8B30
73 #ifndef GL_VERTEX_SHADER
74 #define GL_VERTEX_SHADER 0x8B31
77 #ifndef GL_SHADING_LANGUAGE_VERSION
78 #define GL_SHADING_LANGUAGE_VERSION 0x8B8C
81 #ifndef GL_COMPILE_STATUS
82 #define GL_COMPILE_STATUS 0x8B81
85 #ifndef GL_LINK_STATUS
86 #define GL_LINK_STATUS 0x8B82
89 #ifndef GL_INFO_LOG_LENGTH
90 #define GL_INFO_LOG_LENGTH 0x8B84
93 typedef ptrdiff_t ourGLsizeiptr;
94 typedef char ourGLchar;
100 typedef void (APIENTRY *PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers);
101 PFNGLGENBUFFERSPROC gl_GenBuffers;
103 typedef void (APIENTRY *PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer);
104 PFNGLBINDBUFFERPROC gl_BindBuffer;
106 typedef void (APIENTRY *PFNGLBUFFERDATAPROC) (GLenum target, ourGLsizeiptr size, const GLvoid *data, GLenum usage);
107 PFNGLBUFFERDATAPROC gl_BufferData;
109 typedef GLuint (APIENTRY *PFNGLCREATESHADERPROC) (GLenum type);
110 PFNGLCREATESHADERPROC gl_CreateShader;
112 typedef void (APIENTRY *PFNGLSHADERSOURCEPROC) (GLuint shader, GLsizei count, const ourGLchar **string, const GLint *length);
113 PFNGLSHADERSOURCEPROC gl_ShaderSource;
115 typedef void (APIENTRY *PFNGLCOMPILESHADERPROC) (GLuint shader);
116 PFNGLCOMPILESHADERPROC gl_CompileShader;
118 typedef GLuint (APIENTRY *PFNGLCREATEPROGRAMPROC) (void);
119 PFNGLCREATEPROGRAMPROC gl_CreateProgram;
121 typedef void (APIENTRY *PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader);
122 PFNGLATTACHSHADERPROC gl_AttachShader;
124 typedef void (APIENTRY *PFNGLLINKPROGRAMPROC) (GLuint program);
125 PFNGLLINKPROGRAMPROC gl_LinkProgram;
127 typedef void (APIENTRY *PFNGLUSEPROGRAMPROC) (GLuint program);
128 PFNGLUSEPROGRAMPROC gl_UseProgram;
130 typedef void (APIENTRY *PFNGLGETSHADERIVPROC) (GLuint shader, GLenum pname, GLint *params);
131 PFNGLGETSHADERIVPROC gl_GetShaderiv;
133 typedef void (APIENTRY *PFNGLGETSHADERINFOLOGPROC) (GLuint shader, GLsizei bufSize, GLsizei *length, ourGLchar *infoLog);
134 PFNGLGETSHADERINFOLOGPROC gl_GetShaderInfoLog;
136 typedef void (APIENTRY *PFNGLGETPROGRAMIVPROC) (GLenum target, GLenum pname, GLint *params);
137 PFNGLGETPROGRAMIVPROC gl_GetProgramiv;
139 typedef void (APIENTRY *PFNGLGETPROGRAMINFOLOGPROC) (GLuint program, GLsizei bufSize, GLsizei *length, ourGLchar *infoLog);
140 PFNGLGETPROGRAMINFOLOGPROC gl_GetProgramInfoLog;
142 typedef GLint (APIENTRY *PFNGLGETATTRIBLOCATIONPROC) (GLuint program, const ourGLchar *name);
143 PFNGLGETATTRIBLOCATIONPROC gl_GetAttribLocation;
145 typedef void (APIENTRY *PFNGLVERTEXATTRIBPOINTERPROC) (GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const GLvoid *pointer);
146 PFNGLVERTEXATTRIBPOINTERPROC gl_VertexAttribPointer;
148 typedef void (APIENTRY *PFNGLENABLEVERTEXATTRIBARRAYPROC) (GLuint index);
149 PFNGLENABLEVERTEXATTRIBARRAYPROC gl_EnableVertexAttribArray;
151 typedef GLint (APIENTRY *PFNGLGETUNIFORMLOCATIONPROC) (GLuint program, const ourGLchar *name);
152 PFNGLGETUNIFORMLOCATIONPROC gl_GetUniformLocation;
154 typedef void (APIENTRY *PFNGLUNIFORMMATRIX4FVPROC) (GLint location, GLsizei count, GLboolean transpose, const GLfloat *value);
155 PFNGLUNIFORMMATRIX4FVPROC gl_UniformMatrix4fv;
157 void initExtensionEntries(void)
159 gl_GenBuffers = (PFNGLGENBUFFERSPROC) glutGetProcAddress ("glGenBuffers");
160 gl_BindBuffer = (PFNGLBINDBUFFERPROC) glutGetProcAddress ("glBindBuffer");
161 gl_BufferData = (PFNGLBUFFERDATAPROC) glutGetProcAddress ("glBufferData");
162 gl_CreateShader = (PFNGLCREATESHADERPROC) glutGetProcAddress ("glCreateShader");
163 gl_ShaderSource = (PFNGLSHADERSOURCEPROC) glutGetProcAddress ("glShaderSource");
164 gl_CompileShader = (PFNGLCOMPILESHADERPROC) glutGetProcAddress ("glCompileShader");
165 gl_CreateProgram = (PFNGLCREATEPROGRAMPROC) glutGetProcAddress ("glCreateProgram");
166 gl_AttachShader = (PFNGLATTACHSHADERPROC) glutGetProcAddress ("glAttachShader");
167 gl_LinkProgram = (PFNGLLINKPROGRAMPROC) glutGetProcAddress ("glLinkProgram");
168 gl_UseProgram = (PFNGLUSEPROGRAMPROC) glutGetProcAddress ("glUseProgram");
169 gl_GetShaderiv = (PFNGLGETSHADERIVPROC) glutGetProcAddress ("glGetShaderiv");
170 gl_GetShaderInfoLog = (PFNGLGETSHADERINFOLOGPROC) glutGetProcAddress ("glGetShaderInfoLog");
171 gl_GetProgramiv = (PFNGLGETPROGRAMIVPROC) glutGetProcAddress ("glGetProgramiv");
172 gl_GetProgramInfoLog = (PFNGLGETPROGRAMINFOLOGPROC) glutGetProcAddress ("glGetProgramInfoLog");
173 gl_GetAttribLocation = (PFNGLGETATTRIBLOCATIONPROC) glutGetProcAddress ("glGetAttribLocation");
174 gl_VertexAttribPointer = (PFNGLVERTEXATTRIBPOINTERPROC) glutGetProcAddress ("glVertexAttribPointer");
175 gl_EnableVertexAttribArray = (PFNGLENABLEVERTEXATTRIBARRAYPROC) glutGetProcAddress ("glEnableVertexAttribArray");
176 gl_GetUniformLocation = (PFNGLGETUNIFORMLOCATIONPROC) glutGetProcAddress ("glGetUniformLocation");
177 gl_UniformMatrix4fv = (PFNGLUNIFORMMATRIX4FVPROC) glutGetProcAddress ("glUniformMatrix4fv");
180 /* vertex array data for a colored 2D triangle, consisting of RGB color values
181 and XY coordinates */
182 const GLfloat varray[] = {
183 1.0f, 0.0f, 0.0f, /* red */
184 5.0f, 5.0f, /* lower left */
186 0.0f, 1.0f, 0.0f, /* green */
187 25.0f, 5.0f, /* lower right */
189 0.0f, 0.0f, 1.0f, /* blue */
190 5.0f, 25.0f /* upper left */
193 /* ISO C somehow enforces this silly use of 'enum' for compile-time constants */
195 numColorComponents = 3,
196 numVertexComponents = 2,
197 stride = sizeof(GLfloat) * (numColorComponents + numVertexComponents),
198 numElements = sizeof(varray) / stride
201 /* the name of the vertex buffer object */
202 GLuint vertexBufferName;
204 void initBuffer(void)
206 gl_GenBuffers (1, &vertexBufferName);
207 gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName);
208 gl_BufferData (GL_ARRAY_BUFFER, sizeof(varray), varray, GL_STATIC_DRAW);
209 checkError ("initBuffer");
212 const ourGLchar *vertexShaderSource[] = {
214 "uniform mat4 fg_ProjectionMatrix;\n",
215 "in vec4 fg_Color;\n",
216 "in vec4 fg_Vertex;\n",
219 " gl_FrontColor = fg_Color;\n",
220 " gl_Position = fg_ProjectionMatrix * fg_Vertex;\n",
224 const ourGLchar *fragmentShaderSource[] = {
226 "out vec4 fg_FragColor;\n",
229 " fg_FragColor = gl_Color;\n",
233 void compileAndCheck(GLuint shader)
236 gl_CompileShader (shader);
237 gl_GetShaderiv (shader, GL_COMPILE_STATUS, &status);
238 if (status == GL_FALSE) {
241 gl_GetShaderiv (shader, GL_INFO_LOG_LENGTH, &infoLogLength);
242 infoLog = (ourGLchar*) malloc (infoLogLength);
243 gl_GetShaderInfoLog (shader, infoLogLength, NULL, infoLog);
244 fprintf (stderr, "compile log: %s\n", infoLog);
249 GLuint compileShaderSource(GLenum type, GLsizei count, const ourGLchar **string)
251 GLuint shader = gl_CreateShader (type);
252 gl_ShaderSource (shader, count, string, NULL);
253 compileAndCheck (shader);
257 void linkAndCheck(GLuint program)
260 gl_LinkProgram (program);
261 gl_GetProgramiv (program, GL_LINK_STATUS, &status);
262 if (status == GL_FALSE) {
265 gl_GetProgramiv (program, GL_INFO_LOG_LENGTH, &infoLogLength);
266 infoLog = (ourGLchar*) malloc (infoLogLength);
267 gl_GetProgramInfoLog (program, infoLogLength, NULL, infoLog);
268 fprintf (stderr, "link log: %s\n", infoLog);
273 GLuint createProgram(GLuint vertexShader, GLuint fragmentShader)
275 GLuint program = gl_CreateProgram ();
276 if (vertexShader != 0) {
277 gl_AttachShader (program, vertexShader);
279 if (fragmentShader != 0) {
280 gl_AttachShader (program, fragmentShader);
282 linkAndCheck (program);
286 GLuint fgProjectionMatrixIndex;
288 GLuint fgVertexIndex;
290 void initShader(void)
292 const GLsizei vertexShaderLines = sizeof(vertexShaderSource) / sizeof(ourGLchar*);
293 GLuint vertexShader =
294 compileShaderSource (GL_VERTEX_SHADER, vertexShaderLines, vertexShaderSource);
296 const GLsizei fragmentShaderLines = sizeof(fragmentShaderSource) / sizeof(ourGLchar*);
297 GLuint fragmentShader =
298 compileShaderSource (GL_FRAGMENT_SHADER, fragmentShaderLines, fragmentShaderSource);
300 GLuint program = createProgram (vertexShader, fragmentShader);
302 gl_UseProgram (program);
304 fgProjectionMatrixIndex = gl_GetUniformLocation(program, "fg_ProjectionMatrix");
306 fgColorIndex = gl_GetAttribLocation(program, "fg_Color");
307 gl_EnableVertexAttribArray (fgColorIndex);
309 fgVertexIndex = gl_GetAttribLocation(program, "fg_Vertex");
310 gl_EnableVertexAttribArray (fgVertexIndex);
312 checkError ("initShader");
315 void initRendering(void)
317 glClearColor (0.0, 0.0, 0.0, 0.0);
318 glShadeModel (GL_SMOOTH);
319 checkError ("initRendering");
324 initExtensionEntries ();
332 printf ("Vendor: %s\n", glGetString (GL_VENDOR));
333 printf ("Renderer: %s\n", glGetString (GL_RENDERER));
334 printf ("Version: %s\n", glGetString (GL_VERSION));
335 printf ("GLSL: %s\n", glGetString (GL_SHADING_LANGUAGE_VERSION));
336 checkError ("dumpInfo");
339 const GLvoid *bufferObjectPtr (GLsizei index)
341 return (const GLvoid *) (((char *) NULL) + index);
344 GLfloat projectionMatrix[16];
348 gl_UniformMatrix4fv (fgProjectionMatrixIndex, 1, GL_FALSE, projectionMatrix);
350 gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName);
351 gl_VertexAttribPointer (fgColorIndex, numColorComponents, GL_FLOAT, GL_FALSE,
352 stride, bufferObjectPtr (0));
353 gl_VertexAttribPointer (fgVertexIndex, numVertexComponents, GL_FLOAT, GL_FALSE,
354 stride, bufferObjectPtr (sizeof(GLfloat) * numColorComponents));
355 glDrawArrays(GL_TRIANGLES, 0, numElements);
356 checkError ("triangle");
361 glClear (GL_COLOR_BUFFER_BIT);
364 checkError ("display");
367 void loadOrthof(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t,
368 GLfloat n, GLfloat f)
370 m[ 0] = 2.0f / (r - l);
376 m[ 5] = 2.0f / (t - b);
382 m[10] = -2.0f / (f - n);
385 m[12] = -(r + l) / (r - l);
386 m[13] = -(t + b) / (t - b);
387 m[14] = -(f + n) / (f - n);
391 void loadOrtho2Df(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t)
393 loadOrthof (m, l, r, b, t, -1.0f, 1.0f);
396 void reshape (int w, int h)
398 glViewport (0, 0, (GLsizei) w, (GLsizei) h);
400 loadOrtho2Df (projectionMatrix, 0.0, 30.0, 0.0, 30.0 * (GLfloat) h/(GLfloat) w);
402 loadOrtho2Df (projectionMatrix, 0.0, 30.0 * (GLfloat) w/(GLfloat) h, 0.0, 30.0);
404 checkError ("reshape");
407 void keyboard(unsigned char key, int x, int y)
416 int main(int argc, char** argv)
418 glutInit(&argc, argv);
419 glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
420 /* add command line argument "classic" for a pre-3.0 context */
421 if ((argc != 2) || (strcmp (argv[1], "classic") != 0)) {
422 glutInitContextVersion (3, 0);
423 glutInitContextFlags (GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG);
425 glutInitWindowSize (500, 500);
426 glutInitWindowPosition (100, 100);
427 glutCreateWindow (argv[0]);
430 glutDisplayFunc(display);
431 glutReshapeFunc(reshape);
432 glutKeyboardFunc (keyboard);