Change to using GLEW everywhere.
[movit] / ycbcr_input.cpp
1 #include <string.h>
2 #include <assert.h>
3 #include <GL/glew.h>
4
5 #include <Eigen/LU>
6
7 #include "ycbcr_input.h"
8 #include "util.h"
9
10 using namespace Eigen;
11
12 namespace {
13
14 // OpenGL has texel center in (0.5, 0.5), but different formats have
15 // chroma in various other places. If luma samples are X, the chroma
16 // sample is *, and subsampling is 3x3, the situation with chroma
17 // center in (0.5, 0.5) looks approximately like this:
18 //
19 //   X   X
20 //     *   
21 //   X   X
22 //
23 // If, on the other hand, chroma center is in (0.0, 0.5) (common
24 // for e.g. MPEG-4), the figure changes to:
25 //
26 //   X   X
27 //   *      
28 //   X   X
29 //
30 // In other words, (0.0, 0.0) means that the chroma sample is exactly
31 // co-sited on top of the top-left luma sample. Note, however, that
32 // this is _not_ 0.5 texels to the left, since the OpenGL's texel center
33 // is in (0.5, 0.5); it is in (0.25, 0.25). In a sense, the four luma samples
34 // define a square where chroma position (0.0, 0.0) is in texel position
35 // (0.25, 0.25) and chroma position (1.0, 1.0) is in texel position (0.75, 0.75)
36 // (the outer border shows the borders of the texel itself, ie. from
37 // (0, 0) to (1, 1)):
38 //
39 //  ---------
40 // |         |
41 // |  X---X  |
42 // |  | * |  |
43 // |  X---X  |
44 // |         |
45 //  ---------
46 //
47 // Also note that if we have no subsampling, the square will have zero
48 // area and the chroma position does not matter at all.
49 float compute_chroma_offset(float pos, unsigned subsampling_factor, unsigned resolution)
50 {
51         float local_chroma_pos = (0.5 + pos * (subsampling_factor - 1)) / subsampling_factor;
52         return (0.5 - local_chroma_pos) / resolution;
53 }
54
55 }  // namespace
56
57 YCbCrInput::YCbCrInput(const ImageFormat &image_format,
58                        const YCbCrFormat &ycbcr_format,
59                        unsigned width, unsigned height)
60         : image_format(image_format),
61           ycbcr_format(ycbcr_format),
62           needs_update(false),
63           needs_pbo_recreate(false),
64           finalized(false),
65           needs_mipmaps(false),
66           width(width),
67           height(height)
68 {
69         pbos[0] = pbos[1] = pbos[2] = 0;
70         texture_num[0] = texture_num[1] = texture_num[2] = 0;
71
72         assert(width % ycbcr_format.chroma_subsampling_x == 0);
73         pitch[0] = widths[0] = width;
74         pitch[1] = widths[1] = width / ycbcr_format.chroma_subsampling_x;
75         pitch[2] = widths[2] = width / ycbcr_format.chroma_subsampling_x;
76
77         assert(height % ycbcr_format.chroma_subsampling_y == 0);
78         heights[0] = height;
79         heights[1] = height / ycbcr_format.chroma_subsampling_y;
80         heights[2] = height / ycbcr_format.chroma_subsampling_y;
81
82         register_int("needs_mipmaps", &needs_mipmaps);
83 }
84
85 YCbCrInput::~YCbCrInput()
86 {
87         if (pbos[0] != 0) {
88                 glDeleteBuffers(3, pbos);
89                 check_error();
90         }
91         if (texture_num[0] != 0) {
92                 glDeleteTextures(3, texture_num);
93                 check_error();
94         }
95 }
96
97 void YCbCrInput::finalize()
98 {
99         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
100         check_error();
101
102         // Create PBOs to hold the textures holding the input image, and then the texture itself.
103         glGenBuffers(3, pbos);
104         check_error();
105         glGenTextures(3, texture_num);
106         check_error();
107
108         for (unsigned channel = 0; channel < 3; ++channel) {
109                 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbos[channel]);
110                 check_error();
111                 glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, pitch[channel] * heights[channel], NULL, GL_STREAM_DRAW);
112                 check_error();
113                 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
114                 check_error();
115                 
116                 glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
117                 check_error();
118                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
119                 check_error();
120                 glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch[channel]);
121                 check_error();
122                 glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE8, widths[channel], heights[channel], 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, NULL);
123                 check_error();
124                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
125                 check_error();
126         }
127
128         needs_update = true;
129         finalized = true;
130 }
131         
132 void YCbCrInput::set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num)
133 {
134         for (unsigned channel = 0; channel < 3; ++channel) {
135                 glActiveTexture(GL_TEXTURE0 + *sampler_num + channel);
136                 check_error();
137                 glBindTexture(GL_TEXTURE_2D, texture_num[channel]);
138                 check_error();
139
140                 if (needs_update || needs_pbo_recreate) {
141                         // Copy the pixel data into the PBO.
142                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbos[channel]);
143                         check_error();
144
145                         if (needs_pbo_recreate) {
146                                 // The pitch has changed; we need to reallocate this PBO.
147                                 glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, pitch[channel] * heights[channel], NULL, GL_STREAM_DRAW);
148                                 check_error();
149                         }
150
151                         void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
152                         memcpy(mapped_pbo, pixel_data[channel], pitch[channel] * heights[channel]);
153
154                         glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
155                         check_error();
156
157                         // Re-upload the texture from the PBO.
158                         glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch[channel]);
159                         check_error();
160                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, widths[channel], heights[channel], GL_LUMINANCE, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
161                         check_error();
162                         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
163                         check_error();
164                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
165                         check_error();
166                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
167                         check_error();
168                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
169                         check_error();
170                 }
171         }
172
173         // Bind samplers.
174         set_uniform_int(glsl_program_num, prefix, "tex_y", *sampler_num + 0);
175         set_uniform_int(glsl_program_num, prefix, "tex_cb", *sampler_num + 1);
176         set_uniform_int(glsl_program_num, prefix, "tex_cr", *sampler_num + 2);
177
178         *sampler_num += 3;
179         needs_update = false;
180         needs_pbo_recreate = false;
181 }
182
183 std::string YCbCrInput::output_fragment_shader()
184 {
185         float coeff[3], offset[3], scale[3];
186
187         switch (ycbcr_format.luma_coefficients) {
188         case YCBCR_REC_601:
189                 // Rec. 601, page 2.
190                 coeff[0] = 0.299;
191                 coeff[1] = 0.587;
192                 coeff[2] = 0.114;
193                 break;
194
195         case YCBCR_REC_709:
196                 // Rec. 709, page 19.
197                 coeff[0] = 0.2126;
198                 coeff[1] = 0.7152;
199                 coeff[2] = 0.0722;
200                 break;
201         default:
202                 assert(false);
203         }
204
205         if (ycbcr_format.full_range) {
206                 offset[0] = 0.0 / 255.0;
207                 offset[1] = 128.0 / 255.0;
208                 offset[2] = 128.0 / 255.0;
209
210                 scale[0] = 1.0;
211                 scale[1] = 1.0;
212                 scale[2] = 1.0;
213         } else {
214                 // Rec. 601, page 4; Rec. 709, page 19.
215                 offset[0] = 16.0 / 255.0;
216                 offset[1] = 128.0 / 255.0;
217                 offset[2] = 128.0 / 255.0;
218
219                 scale[0] = 255.0 / 219.0;
220                 scale[1] = 255.0 / 224.0;
221                 scale[2] = 255.0 / 224.0;
222         }
223
224         // Matrix to convert RGB to YCbCr. See e.g. Rec. 601.
225         Matrix3d rgb_to_ycbcr;
226         rgb_to_ycbcr(0,0) = coeff[0];
227         rgb_to_ycbcr(0,1) = coeff[1];
228         rgb_to_ycbcr(0,2) = coeff[2];
229
230         float cb_fac = (224.0 / 219.0) / (coeff[0] + coeff[1] + 1.0f - coeff[2]);
231         rgb_to_ycbcr(1,0) = -coeff[0] * cb_fac;
232         rgb_to_ycbcr(1,1) = -coeff[1] * cb_fac;
233         rgb_to_ycbcr(1,2) = (1.0f - coeff[2]) * cb_fac;
234
235         float cr_fac = (224.0 / 219.0) / (1.0f - coeff[0] + coeff[1] + coeff[2]);
236         rgb_to_ycbcr(2,0) = (1.0f - coeff[0]) * cr_fac;
237         rgb_to_ycbcr(2,1) = -coeff[1] * cr_fac;
238         rgb_to_ycbcr(2,2) = -coeff[2] * cr_fac;
239
240         // Inverting the matrix gives us what we need to go from YCbCr back to RGB.
241         Matrix3d ycbcr_to_rgb = rgb_to_ycbcr.inverse();
242
243         std::string frag_shader;
244
245         frag_shader = output_glsl_mat3("PREFIX(inv_ycbcr_matrix)", ycbcr_to_rgb);
246
247         char buf[256];
248         sprintf(buf, "const vec3 PREFIX(offset) = vec3(%.8f, %.8f, %.8f);\n",
249                 offset[0], offset[1], offset[2]);
250         frag_shader += buf;
251
252         sprintf(buf, "const vec3 PREFIX(scale) = vec3(%.8f, %.8f, %.8f);\n",
253                 scale[0], scale[1], scale[2]);
254         frag_shader += buf;
255
256         float cb_offset_x = compute_chroma_offset(
257                 ycbcr_format.cb_x_position, ycbcr_format.chroma_subsampling_x, widths[1]);
258         float cb_offset_y = compute_chroma_offset(
259                 ycbcr_format.cb_y_position, ycbcr_format.chroma_subsampling_y, heights[1]);
260         sprintf(buf, "const vec2 PREFIX(cb_offset) = vec2(%.8f, %.8f);\n",
261                 cb_offset_x, cb_offset_y);
262         frag_shader += buf;
263
264         float cr_offset_x = compute_chroma_offset(
265                 ycbcr_format.cr_x_position, ycbcr_format.chroma_subsampling_x, widths[2]);
266         float cr_offset_y = compute_chroma_offset(
267                 ycbcr_format.cr_y_position, ycbcr_format.chroma_subsampling_y, heights[2]);
268         sprintf(buf, "const vec2 PREFIX(cr_offset) = vec2(%.8f, %.8f);\n",
269                 cr_offset_x, cr_offset_y);
270         frag_shader += buf;
271
272         frag_shader += read_file("ycbcr_input.frag");
273         return frag_shader;
274 }