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
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#ifdef GLSLWRITE
# include <png.h>
#endif
#include <GL/glew.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>
#ifdef GLSLWRITE
static unsigned frame_time = 0;
#endif
static GLint time_loc;
static GLint res_loc;
static char * readfile(const char *filename) {
FILE *f = fopen(filename, "r");
if (!f)
return NULL;
size_t size = 1024;
char *buffer = malloc(size+1);
size_t count = 0, r;
do {
if (count == size) {
size *= 2;
buffer = realloc(buffer, size+1);
}
r = fread(buffer+count, 1, size-count, f);
count += r;
} while (r);
fclose(f);
buffer[count] = 0;
return buffer;
}
static void printShaderInfoLog(GLuint obj) {
GLint length = 0;
glGetShaderiv(obj, GL_INFO_LOG_LENGTH, &length);
if(length > 0) {
char log[length];
glGetShaderInfoLog(obj, sizeof(log), NULL, log);
fprintf(stderr, "%s\n", log);
}
}
static void printProgramInfoLog(GLuint obj) {
GLint length = 0;
glGetProgramiv(obj, GL_INFO_LOG_LENGTH, &length);
if(length > 0) {
char log[length];
glGetProgramInfoLog(obj, sizeof(log), NULL, log);
fprintf(stderr, "%s\n", log);
}
}
static void init(char *filename) {
glewInit();
glDisable(GL_DEPTH_TEST);
char *shader = readfile(filename);
if (!shader) {
fprintf(stderr, "Error: unable to read '%s'\n", filename);
exit(1);
}
GLuint frag = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(frag, 1, (const GLchar **)&shader, NULL);
glCompileShader(frag);
printShaderInfoLog(frag);
GLuint program = glCreateProgram();
glAttachShader(program, frag);
glLinkProgram(program);
printProgramInfoLog(program);
glBindFragDataLocation(program, 0, "fragColor");
time_loc = glGetUniformLocation(program, "time");
res_loc = glGetUniformLocation(program, "res");
glUseProgram(program);
}
#ifdef GLSLWRITE
static void savePNG(int width, int height, const char *output_dir) {
uint8_t pixels[width*height*4];
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, pixels);
char filename[strlen(output_dir) + 20];
snprintf(filename, sizeof(filename), "%s/%010u.png", output_dir, frame_time);
FILE *f = fopen(filename, "wb");
if (!f) {
fprintf(stderr, "unable to open PNG file\n");
exit(1);
}
png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr) {
fprintf(stderr, "unable to open PNG file\n");
exit(1);
}
png_set_swap_alpha(png_ptr);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
fprintf(stderr, "unable to create PNG info struct\n");
exit(1);
}
if (setjmp(png_jmpbuf(png_ptr))) {
fprintf(stderr, "unable to write PNG file\n");
exit(1);
}
png_init_io(png_ptr, f);
png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
uint8_t *row_pointers[height];
for (size_t i = 0; i < height; i++)
row_pointers[i] = &pixels[4*i*width];
png_set_rows(png_ptr, info_ptr, row_pointers);
png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
png_destroy_write_struct(&png_ptr, &info_ptr);
fclose(f);
}
#endif
static void render(int width, int height) {
glViewport(0, 0, (GLsizei)width, (GLsizei)height);
#ifdef GLSLWRITE
glUniform1f(time_loc, frame_time);
#else
glUniform1f(time_loc, SDL_GetTicks());
#endif
glUniform2f(res_loc, width, height);
glBegin(GL_QUADS);
glVertex2f(-1, -1);
glVertex2f(1, -1);
glVertex2f(1, 1);
glVertex2f(-1, 1);
glEnd();
#ifdef GLSLWRITE
frame_time += 20;
#endif
}
int main(int argc, char *argv[]) {
bool running = true;
#ifdef GLSLWRITE
if (argc != 3) {
fprintf(stderr, "Usage: glslwrite <shader> <output directory>\n");
exit(1);
}
#else
if (argc != 2) {
fprintf(stderr, "Usage: glslview <shader> <output directory>\n");
exit(1);
}
#endif
SDL_Init(SDL_INIT_VIDEO);
SDL_Window *window = SDL_CreateWindow("glslwrite", 0, 0, 800, 800, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
SDL_GL_CreateContext(window);
init(argv[1]);
while (running) {
SDL_Event e;
while( SDL_PollEvent(&e)) {
if(e.type == SDL_QUIT) {
running = false;
break;
}
}
int width, height;
SDL_GetWindowSize(window, &width, &height);
render(width, height);
SDL_GL_SwapWindow(window);
#ifdef GLSLWRITE
savePNG(width, height, argv[2]);
#endif
}
return 0;
}
|
