1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
#include "OffscreenContext.h"
#include "printutils.h"
#include "lodepng.h"
// see http://www.gamedev.net/topic/552607-conflict-between-glew-and-sdl/
#define NO_SDL_GLEXT
#include <GL/glew.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glext.h>
//#include <GL/gl.h>
//#include <GL/glu.h> // for gluCheckExtension
#include <SDL.h>
// Simple error reporting macros to help keep the sample code clean
#define REPORT_ERROR_AND_EXIT(desc) { std::cout << desc << "\n"; return false; }
#define NULL_ERROR_EXIT(test, desc) { if (!test) REPORT_ERROR_AND_EXIT(desc); }
struct OffscreenContext
{
int width;
int height;
GLuint fbo;
GLuint colorbo;
GLuint depthbo;
};
void write_targa(const char *filename, GLubyte *pixels, int width, int height)
{
FILE *f = fopen( filename, "w" );
int y;
if (f) {
GLubyte header[] = {
00,00,02, 00,00,00, 00,00,00, 00,00,00,
0xff & width, 0xff & width >> 8,
0xff & height, 0xff & height >> 8,
32, 0x20 }; // next-to-last = bit depth
fwrite( header, sizeof(header), 1, f);
for (y=height-1; y>=0; y--)
fwrite( pixels + y*width*4, 4, width, f);
fclose(f);
}
}
void write_png(const char *filename, GLubyte *pixels, int width, int height)
{
size_t pixel_size = 4;
size_t dataout_size = -1;
GLubyte *dataout = (GLubyte*)malloc(width*height*pixel_size); // freed below
GLubyte *pixels_flipped = (GLubyte*)malloc(width*height*pixel_size); // freed below
for (int y=0;y<height;y++) {
for (int x=0;x<width;x++) {
int offs1 = y*width*pixel_size + x*pixel_size;
int offs2 = (height-1-y)*width*pixel_size + x*pixel_size;
pixels_flipped[offs1 ] = pixels[offs2 ];
pixels_flipped[offs1+1] = pixels[offs2+1];
pixels_flipped[offs1+2] = pixels[offs2+2];
pixels_flipped[offs1+3] = pixels[offs2+3];
}
}
//encoder.settings.zlibsettings.windowSize = 2048;
//LodePNG_Text_add(&encoder.infoPng.text, "Comment", "Created with LodePNG");
LodePNG_encode(&dataout, &dataout_size, pixels_flipped, width, height, LCT_RGBA, 8);
//LodePNG_saveFile(dataout, dataout_size, "blah2.png");
FILE *f = fopen( filename, "w" );
if (f) {
fwrite( dataout, 1, dataout_size, f);
fclose(f);
}
free(pixels_flipped);
free(dataout);
}
OffscreenContext *create_offscreen_context(int w, int h)
{
OffscreenContext *ctx = new OffscreenContext;
ctx->width = w;
ctx->height = h;
// dummy window
SDL_Init(SDL_INIT_VIDEO);
SDL_SetVideoMode(ctx->width,ctx->height,32,SDL_OPENGL);
// must come after openGL context init (done by dummy window)
// but must also come before various EXT calls
//glewInit();
/*
// Test if framebuffer objects are supported
const GLubyte* strExt = glGetString(GL_EXTENSIONS);
GLboolean fboSupported = gluCheckExtension((const GLubyte*)"GL_EXT_framebuffer_object", strExt);
if (!fboSupported)
REPORT_ERROR_AND_EXIT("Your system does not support framebuffer extension - unable to render scene");
printf("%i\n", (int)glGenFramebuffersEXT);
GLuint fbo;
//ctx->fbo = 0;
glGenFramebuffersEXT(1, &fbo);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
REPORTGLERROR("binding framebuffer");
GLuint renderBuffer = 0;
GLuint depthBuffer = 0;
// Depth buffer to use for depth testing - optional if you're not using depth testing
glGenRenderbuffersEXT(1, &depthBuffer);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthBuffer);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, w, h);
REPORTGLERROR("creating depth render buffer");
// Render buffer to use for imaging
glGenRenderbuffersEXT(1, &renderBuffer);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, renderBuffer);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGBA8, w, h);
REPORTGLERROR("creating color render buffer");
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_RENDERBUFFER_EXT, renderBuffer);
REPORTGLERROR("specifying color render buffer");
if (glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) !=
GL_FRAMEBUFFER_COMPLETE_EXT)
REPORT_ERROR_AND_EXIT("Problem with OpenGL framebuffer after specifying color render buffer.");
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
GL_RENDERBUFFER_EXT, depthBuffer);
REPORTGLERROR("specifying depth render buffer");
if (glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) !=
GL_FRAMEBUFFER_COMPLETE_EXT)
REPORT_ERROR_AND_EXIT("Problem with OpenGL framebuffer after specifying depth render buffer.");
*/
/*
glClearColor(1, 1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_TRIANGLES);
glColor3f( 1, 0, 0);
glVertex3f( 0, 0, 0);
glVertex3f( 1, 0, 0);
glVertex3f( 0, 1, 0);
glEnd();
SDL_GL_SwapBuffers();
// sleep(2);
*/
int samplesPerPixel = 4; // R, G, B and A
/* char * filename = "blah.tga";
GLubyte pixels[ ctx->width * ctx->height * samplesPerPixel ];
glReadPixels(0, 0, ctx->width, ctx->height, GL_BGRA, GL_UNSIGNED_BYTE, pixels);
printf("writing %s\n",filename);
write_targa(filename,pixels,ctx->width, ctx->height);*/
return ctx;
}
bool teardown_offscreen_context(OffscreenContext *ctx)
{
// "un"bind my FBO
// glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
/*
* Cleanup
*/
return true;
}
bool save_framebuffer(OffscreenContext *ctx, const char *filename)
{
/*
* Extract the resulting rendering as an image
*/
SDL_GL_SwapBuffers(); // show image
int samplesPerPixel = 4; // R, G, B and A
GLubyte pixels[ ctx->width * ctx->height * samplesPerPixel ];
glReadPixels(0, 0, ctx->width, ctx->height, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
//char * filename2="blah2.tga";
//PRINTF("writing %s\n",filename2);
//write_targa(filename2,pixels,ctx->width, ctx->height);
//char * filename2="blah2.png";
PRINTF("writing %s . . .",filename);
//write_targa(filename2,pixels,ctx->width, ctx->height);
write_png(filename,pixels,ctx->width, ctx->height);
PRINTF("written\n");
return true;
}
void bind_offscreen_context(OffscreenContext *ctx)
{
// glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, ctx->fbo);
}
|
