309 lines
8.2 KiB
C
309 lines
8.2 KiB
C
/*
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* Demo of off-screen Mesa rendering with 32-bit float color channels.
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* This requires the libOSMesa32.so library.
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*
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* Compile with something like this:
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*
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* gcc osdemo32.c -I../../include -L../../lib -lglut -lGLU -lOSMesa32 -lm -o osdemo32
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "GL/osmesa.h"
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#include "GL/glut.h"
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#define SAVE_TARGA
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#define WIDTH 400
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#define HEIGHT 400
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static void render_image( void )
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{
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GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
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GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
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GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
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GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
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GLfloat red_mat[] = { 1.0, 0.2, 0.2, 1.0 };
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GLfloat green_mat[] = { 0.2, 1.0, 0.2, 0.5 };
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GLfloat blue_mat[] = { 0.2, 0.2, 1.0, 1.0 };
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GLfloat white_mat[] = { 1.0, 1.0, 1.0, 1.0 };
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GLfloat purple_mat[] = { 1.0, 0.2, 1.0, 1.0 };
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GLUquadricObj *qobj = gluNewQuadric();
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glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
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glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
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glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
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glLightfv(GL_LIGHT0, GL_POSITION, light_position);
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glEnable(GL_DEPTH_TEST);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(-2.5, 2.5, -2.5, 2.5, -10.0, 10.0);
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glMatrixMode(GL_MODELVIEW);
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glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
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glPushMatrix();
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glRotatef(20.0, 1.0, 0.0, 0.0);
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#if 0
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glPushMatrix();
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glTranslatef(-0.75, 0.5, 0.0);
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glRotatef(90.0, 1.0, 0.0, 0.0);
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glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, red_mat );
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glutSolidTorus(0.275, 0.85, 20, 20);
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glPopMatrix();
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#endif
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/* red square */
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glPushMatrix();
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glTranslatef(0.0, -0.5, 0.0);
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glRotatef(90, 1, 0.5, 0);
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glScalef(3, 3, 3);
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glDisable(GL_LIGHTING);
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glColor4f(1, 0, 0, 0.5);
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glBegin(GL_POLYGON);
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glVertex2f(-1, -1);
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glVertex2f( 1, -1);
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glVertex2f( 1, 1);
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glVertex2f(-1, 1);
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glEnd();
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glEnable(GL_LIGHTING);
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glPopMatrix();
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#if 0
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/* green square */
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glPushMatrix();
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glTranslatef(0.0, 0.5, 0.1);
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glDisable(GL_LIGHTING);
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glColor3f(0, 1, 0);
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glBegin(GL_POLYGON);
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glVertex2f(-1, -1);
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glVertex2f( 1, -1);
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glVertex2f( 1, 1);
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glVertex2f(-1, 1);
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glEnd();
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glEnable(GL_LIGHTING);
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glPopMatrix();
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/* blue square */
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glPushMatrix();
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glTranslatef(0.75, 0.5, 0.3);
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glDisable(GL_LIGHTING);
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glColor3f(0, 0, 0.5);
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glBegin(GL_POLYGON);
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glVertex2f(-1, -1);
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glVertex2f( 1, -1);
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glVertex2f( 1, 1);
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glVertex2f(-1, 1);
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glEnd();
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glEnable(GL_LIGHTING);
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glPopMatrix();
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#endif
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glPushMatrix();
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glTranslatef(-0.75, -0.5, 0.0);
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glRotatef(270.0, 1.0, 0.0, 0.0);
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glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, green_mat );
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glColor4f(0,1,0,0.5);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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gluCylinder(qobj, 1.0, 0.0, 2.0, 16, 1);
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glDisable(GL_BLEND);
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glPopMatrix();
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glPushMatrix();
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glTranslatef(0.75, 1.0, 1.0);
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glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blue_mat );
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gluSphere(qobj, 1.0, 20, 20);
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glPopMatrix();
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glPopMatrix();
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/* This is very important!!!
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* Make sure buffered commands are finished!!!
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*/
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glFinish();
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gluDeleteQuadric(qobj);
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{
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GLint r, g, b, a;
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glGetIntegerv(GL_RED_BITS, &r);
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glGetIntegerv(GL_GREEN_BITS, &g);
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glGetIntegerv(GL_BLUE_BITS, &b);
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glGetIntegerv(GL_ALPHA_BITS, &a);
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printf("channel sizes: %d %d %d %d\n", r, g, b, a);
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}
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}
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static void
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write_targa(const char *filename, const GLfloat *buffer, int width, int height)
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{
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FILE *f = fopen( filename, "w" );
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if (f) {
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int i, x, y;
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const GLfloat *ptr = buffer;
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printf ("osdemo, writing tga file \n");
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fputc (0x00, f); /* ID Length, 0 => No ID */
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fputc (0x00, f); /* Color Map Type, 0 => No color map included */
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fputc (0x02, f); /* Image Type, 2 => Uncompressed, True-color Image */
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fputc (0x00, f); /* Next five bytes are about the color map entries */
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fputc (0x00, f); /* 2 bytes Index, 2 bytes length, 1 byte size */
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fputc (0x00, f);
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fputc (0x00, f);
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fputc (0x00, f);
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fputc (0x00, f); /* X-origin of Image */
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fputc (0x00, f);
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fputc (0x00, f); /* Y-origin of Image */
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fputc (0x00, f);
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fputc (WIDTH & 0xff, f); /* Image Width */
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fputc ((WIDTH>>8) & 0xff, f);
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fputc (HEIGHT & 0xff, f); /* Image Height */
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fputc ((HEIGHT>>8) & 0xff, f);
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fputc (0x18, f); /* Pixel Depth, 0x18 => 24 Bits */
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fputc (0x20, f); /* Image Descriptor */
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fclose(f);
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f = fopen( filename, "ab" ); /* reopen in binary append mode */
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for (y=height-1; y>=0; y--) {
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for (x=0; x<width; x++) {
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int r, g, b;
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i = (y*width + x) * 4;
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r = (int) (ptr[i+0] * 255.0);
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g = (int) (ptr[i+1] * 255.0);
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b = (int) (ptr[i+2] * 255.0);
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if (r > 255) r = 255;
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if (g > 255) g = 255;
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if (b > 255) b = 255;
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fputc(b, f); /* write blue */
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fputc(g, f); /* write green */
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fputc(r, f); /* write red */
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}
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}
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}
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}
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static void
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write_ppm(const char *filename, const GLfloat *buffer, int width, int height)
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{
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const int binary = 0;
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FILE *f = fopen( filename, "w" );
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if (f) {
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int i, x, y;
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const GLfloat *ptr = buffer;
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if (binary) {
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fprintf(f,"P6\n");
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fprintf(f,"# ppm-file created by osdemo.c\n");
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fprintf(f,"%i %i\n", width,height);
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fprintf(f,"255\n");
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fclose(f);
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f = fopen( filename, "ab" ); /* reopen in binary append mode */
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for (y=height-1; y>=0; y--) {
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for (x=0; x<width; x++) {
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int r, g, b;
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i = (y*width + x) * 4;
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r = (int) (ptr[i+0] * 255.0);
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g = (int) (ptr[i+1] * 255.0);
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b = (int) (ptr[i+2] * 255.0);
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if (r > 255) r = 255;
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if (g > 255) g = 255;
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if (b > 255) b = 255;
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fputc(r, f); /* write red */
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fputc(g, f); /* write green */
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fputc(b, f); /* write blue */
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}
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}
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}
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else {
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/*ASCII*/
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int counter = 0;
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fprintf(f,"P3\n");
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fprintf(f,"# ascii ppm file created by osdemo.c\n");
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fprintf(f,"%i %i\n", width, height);
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fprintf(f,"255\n");
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for (y=height-1; y>=0; y--) {
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for (x=0; x<width; x++) {
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int r, g, b;
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i = (y*width + x) * 4;
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r = (int) (ptr[i+0] * 255.0);
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g = (int) (ptr[i+1] * 255.0);
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b = (int) (ptr[i+2] * 255.0);
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if (r > 255) r = 255;
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if (g > 255) g = 255;
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if (b > 255) b = 255;
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fprintf(f, " %3d %3d %3d", r, g, b);
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counter++;
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if (counter % 5 == 0)
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fprintf(f, "\n");
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}
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}
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}
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fclose(f);
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}
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}
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int main( int argc, char *argv[] )
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{
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GLfloat *buffer;
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/* Create an RGBA-mode context */
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#if OSMESA_MAJOR_VERSION * 100 + OSMESA_MINOR_VERSION >= 305
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/* specify Z, stencil, accum sizes */
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OSMesaContext ctx = OSMesaCreateContextExt( GL_RGBA, 16, 0, 0, NULL );
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#else
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OSMesaContext ctx = OSMesaCreateContext( GL_RGBA, NULL );
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#endif
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if (!ctx) {
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printf("OSMesaCreateContext failed!\n");
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return 0;
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}
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/* Allocate the image buffer */
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buffer = (GLfloat *) malloc( WIDTH * HEIGHT * 4 * sizeof(GLfloat));
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if (!buffer) {
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printf("Alloc image buffer failed!\n");
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return 0;
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}
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/* Bind the buffer to the context and make it current */
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if (!OSMesaMakeCurrent( ctx, buffer, GL_FLOAT, WIDTH, HEIGHT )) {
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printf("OSMesaMakeCurrent failed!\n");
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return 0;
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}
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render_image();
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if (argc>1) {
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#ifdef SAVE_TARGA
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write_targa(argv[1], buffer, WIDTH, HEIGHT);
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#else
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write_ppm(argv[1], buffer, WIDTH, HEIGHT);
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#endif
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}
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else {
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printf("Specify a filename if you want to make an image file\n");
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}
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printf("all done\n");
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/* free the image buffer */
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free( buffer );
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/* destroy the context */
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OSMesaDestroyContext( ctx );
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return 0;
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}
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