From 2af3dd1eaeacc9679eac2f4d882dae3f0891f657 Mon Sep 17 00:00:00 2001 From: spanne Date: Sun, 15 Feb 2009 14:00:45 +0000 Subject: [PATCH] Added a commandline option for 'classic' contexts. Aesthetic changes. git-svn-id: https://svn.code.sf.net/p/freeglut/code/trunk@776 7f0cb862-5218-0410-a997-914c9d46530a --- .../demos/smooth_opengl3/smooth_opengl3.c | 95 +++++++++++-------- 1 file changed, 53 insertions(+), 42 deletions(-) diff --git a/freeglut/freeglut/progs/demos/smooth_opengl3/smooth_opengl3.c b/freeglut/freeglut/progs/demos/smooth_opengl3/smooth_opengl3.c index ff7e12b..0d08338 100755 --- a/freeglut/freeglut/progs/demos/smooth_opengl3/smooth_opengl3.c +++ b/freeglut/freeglut/progs/demos/smooth_opengl3/smooth_opengl3.c @@ -47,61 +47,72 @@ #include /* report GL errors, if any, to stderr */ -void reportErrors(const char *message) +void checkError(const char *functionName) { GLenum error; while (( error = glGetError() ) != GL_NO_ERROR) { - fprintf (stderr, "GL error 0x%X %s\n", error, message); + fprintf (stderr, "GL error 0x%X detected in %s\n", error, functionName); } } -/* extension entries */ -void (*gl_GenBuffers) (GLsizei n, GLuint *buffers); -void (*gl_BindBuffer) (GLenum target, GLuint buffer); -void (*gl_BufferData) (GLenum target, GLsizeiptr size, const GLvoid *data, - GLenum usage); +/* extension types and entries, avoiding a dependency on additional libraries + like GLEW or the GL/glext.h header */ +typedef void (*PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers); +PFNGLGENBUFFERSPROC gl_GenBuffers; + +typedef void (*PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer); +PFNGLBINDBUFFERPROC gl_BindBuffer; + +typedef void (*PFNGLBUFFERDATAPROC) (GLenum target, GLsizeiptr size, + const GLvoid *data, GLenum usage); +PFNGLBUFFERDATAPROC gl_BufferData; void initExtensionEntries(void) { - gl_GenBuffers = glutGetProcAddress ("glGenBuffers"); - gl_BindBuffer = glutGetProcAddress ("glBindBuffer"); - gl_BufferData = glutGetProcAddress ("glBufferData"); + gl_GenBuffers = (PFNGLGENBUFFERSPROC) glutGetProcAddress ("glGenBuffers"); + gl_BindBuffer = (PFNGLBINDBUFFERPROC) glutGetProcAddress ("glBindBuffer"); + gl_BufferData = (PFNGLBUFFERDATAPROC) glutGetProcAddress ("glBufferData"); } /* vertex array data for a colored 2D triangle, consisting of RGB color values and XY coordinates */ -const GLsizei numColorComponents = 3; -const GLsizei numVertexComponents = 2; - const GLfloat varray[] = { - 1.0f, 0.0f, 0.0f, - 5.0f, 5.0f, + 1.0f, 0.0f, 0.0f, /* red */ + 5.0f, 5.0f, /* lower left */ - 0.0f, 1.0f, 0.0f, - 25.0f, 5.0f, + 0.0f, 1.0f, 0.0f, /* green */ + 25.0f, 5.0f, /* lower right */ - 0.0f, 0.0f, 1.0f, - 5.0f, 25.0f + 0.0f, 0.0f, 1.0f, /* blue */ + 5.0f, 25.0f /* upper left */ +}; + +/* ISO C somehow enforces this silly use of 'enum' for compile-time constants */ +enum { + numColorComponents = 3, + numVertexComponents = 2, + stride = sizeof(GLfloat) * (numColorComponents + numVertexComponents), + numElements = sizeof(varray) / stride }; /* the name of the vertex buffer object */ -GLuint bufferName; +GLuint vertexBufferName; void initBuffer(void) { - reportErrors ("at start of initBuffer"); - gl_GenBuffers (1, &bufferName); - gl_BindBuffer (GL_ARRAY_BUFFER, bufferName); + gl_GenBuffers (1, &vertexBufferName); + gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName); gl_BufferData (GL_ARRAY_BUFFER, sizeof(varray), varray, GL_STATIC_DRAW); - reportErrors ("at end of initBuffer"); + glEnableClientState (GL_COLOR_ARRAY); + glEnableClientState (GL_VERTEX_ARRAY); + checkError ("initBuffer"); } void initRendering(void) { - reportErrors ("at start of initRendering"); glClearColor (0.0, 0.0, 0.0, 0.0); glShadeModel (GL_SMOOTH); - reportErrors ("at end of initRendering"); + checkError ("initRendering"); } void init(void) @@ -111,29 +122,27 @@ void init(void) initRendering(); } +const GLvoid *bufferObjectPtr (GLsizei index) +{ + return (const GLvoid *) (((char *) NULL) + index); +} + void triangle(void) { - const char *base = NULL; - const GLsizei stride = sizeof(GLfloat) * (numColorComponents + numVertexComponents); - const GLsizei numElements = sizeof(varray) / stride; - reportErrors ("at start of triangle"); - gl_BindBuffer (GL_ARRAY_BUFFER, bufferName); - glColorPointer (numColorComponents, GL_FLOAT, stride, base); + gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName); + glColorPointer (numColorComponents, GL_FLOAT, stride, bufferObjectPtr (0)); glVertexPointer(numVertexComponents, GL_FLOAT, stride, - base + sizeof(GLfloat) * numColorComponents); - glEnableClientState (GL_COLOR_ARRAY); - glEnableClientState (GL_VERTEX_ARRAY); + bufferObjectPtr (sizeof(GLfloat) * numColorComponents)); glDrawArrays(GL_TRIANGLES, 0, numElements); - reportErrors ("at end of triangle"); + checkError ("triangle"); } void display(void) { - reportErrors ("at start of display"); glClear (GL_COLOR_BUFFER_BIT); triangle (); glFlush (); - reportErrors ("at end of display"); + checkError ("display"); } void loadOrthof(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t, @@ -168,7 +177,6 @@ void loadOrtho2Df(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t) void reshape (int w, int h) { GLfloat m[16]; - reportErrors ("at start of reshape"); glViewport (0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode (GL_PROJECTION); if (w <= h) { @@ -178,7 +186,7 @@ void reshape (int w, int h) } glLoadMatrixf (m); glMatrixMode (GL_MODELVIEW); - reportErrors ("at end of reshape"); + checkError ("reshape"); } void keyboard(unsigned char key, int x, int y) @@ -194,8 +202,11 @@ int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); - glutInitContextVersion(3, 0); - /* glutInitContextFlags(GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG); */ + /* add command line argument "classic" for a pre-3.0 context */ + if ((argc != 2) || (strcmp (argv[1], "classic") != 0)) { + glutInitContextVersion (3, 0); + glutInitContextFlags (GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG); + } glutInitWindowSize (500, 500); glutInitWindowPosition (100, 100); glutCreateWindow (argv[0]);