git.sesse.net Git - movit/blob - flat_input.cpp

   1 #include <string.h>
   2 #include <assert.h>
   3
   4 #include "flat_input.h"
   5 #include "util.h"
   6 #include "opengl.h"
   7
   8 FlatInput::FlatInput(ImageFormat image_format, unsigned width, unsigned height)
   9         : image_format(image_format),
  10           needs_update(false),
  11           finalized(false),
  12           output_linear_gamma(false),
  13           needs_mipmaps(false),
  14           width(width),
  15           height(height),
  16           pitch(width)
  17 {
  18         register_int("output_linear_gamma", &output_linear_gamma);
  19         register_int("needs_mipmaps", &needs_mipmaps);
  20 }
  21
  22 void FlatInput::finalize()
  23 {
  24         // Translate the input format to OpenGL's enums.
  25         GLenum internal_format;
  26         if (output_linear_gamma) {
  27                 internal_format = GL_SRGB8;
  28         } else {
  29                 internal_format = GL_RGBA8;
  30         }
  31         if (image_format.pixel_format == FORMAT_RGB) {
  32                 format = GL_RGB;
  33                 bytes_per_pixel = 3;
  34         } else if (image_format.pixel_format == FORMAT_RGBA) {
  35                 format = GL_RGBA;
  36                 bytes_per_pixel = 4;
  37         } else if (image_format.pixel_format == FORMAT_BGR) {
  38                 format = GL_BGR;
  39                 bytes_per_pixel = 3;
  40         } else if (image_format.pixel_format == FORMAT_BGRA) {
  41                 format = GL_BGRA;
  42                 bytes_per_pixel = 4;
  43         } else if (image_format.pixel_format == FORMAT_GRAYSCALE) {
  44                 format = GL_LUMINANCE;
  45                 bytes_per_pixel = 1;
  46         } else {
  47                 assert(false);
  48         }
  49
  50         // Create PBO to hold the texture holding the input image, and then the texture itself.
  51         glGenBuffers(1, &pbo);
  52         check_error();
  53         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
  54         check_error();
  55         glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, pitch * height * bytes_per_pixel, NULL, GL_STREAM_DRAW);
  56         check_error();
  57         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
  58         check_error();
  59
  60         glGenTextures(1, &texture_num);
  61         check_error();
  62         glBindTexture(GL_TEXTURE_2D, texture_num);
  63         check_error();
  64         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  65         check_error();
  66         glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch);
  67         check_error();
  68         // Intel/Mesa seems to have a broken glGenerateMipmap() for non-FBO textures, so do it here
  69         // instead of calling glGenerateMipmap().
  70         glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, needs_mipmaps);
  71         check_error();
  72         glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, NULL);
  73         check_error();
  74         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
  75         check_error();
  76
  77         needs_update = false;
  78         finalized = true;
  79 }
  80
  81 void FlatInput::set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num)
  82 {
  83         glActiveTexture(GL_TEXTURE0 + *sampler_num);
  84         check_error();
  85         glBindTexture(GL_TEXTURE_2D, texture_num);
  86         check_error();
  87
  88         if (needs_update) {
  89                 // Copy the pixel data into the PBO.
  90                 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
  91                 check_error();
  92                 void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
  93                 memcpy(mapped_pbo, pixel_data, pitch * height * bytes_per_pixel);
  94                 glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
  95                 check_error();
  96
  97                 // Re-upload the texture from the PBO.
  98                 glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch);
  99                 check_error();
 100                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
 101                 check_error();
 102                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 103                 check_error();
 104                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 105                 check_error();
 106                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 107                 check_error();
 108                 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
 109                 check_error();
 110
 111                 needs_update = false;
 112         }
 113
 114         // Bind it to a sampler.
 115         set_uniform_int(glsl_program_num, prefix, "tex", *sampler_num);
 116         ++*sampler_num;
 117 }
 118
 119 std::string FlatInput::output_fragment_shader()
 120 {
 121         return read_file("flat_input.frag");
 122 }