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

   1 #define GL_GLEXT_PROTOTYPES 1
   2
   3 #include <string.h>
   4 #include <GL/gl.h>
   5 #include <GL/glext.h>
   6 #include <assert.h>
   7
   8 #include "flat_input.h"
   9 #include "util.h"
  10
  11 FlatInput::FlatInput(ImageFormat image_format, unsigned width, unsigned height)
  12         : image_format(image_format),
  13           needs_update(false),
  14           finalized(false),
  15           output_linear_gamma(false),
  16           needs_mipmaps(false),
  17           width(width),
  18           height(height),
  19           pitch(width)
  20 {
  21         register_int("output_linear_gamma", &output_linear_gamma);
  22         register_int("needs_mipmaps", &needs_mipmaps);
  23 }
  24
  25 void FlatInput::finalize()
  26 {
  27         // Translate the input format to OpenGL's enums.
  28         GLenum internal_format;
  29         if (output_linear_gamma) {
  30                 internal_format = GL_SRGB8;
  31         } else {
  32                 internal_format = GL_RGBA8;
  33         }
  34         if (image_format.pixel_format == FORMAT_RGB) {
  35                 format = GL_RGB;
  36                 bytes_per_pixel = 3;
  37         } else if (image_format.pixel_format == FORMAT_RGBA) {
  38                 format = GL_RGBA;
  39                 bytes_per_pixel = 4;
  40         } else if (image_format.pixel_format == FORMAT_BGR) {
  41                 format = GL_BGR;
  42                 bytes_per_pixel = 3;
  43         } else if (image_format.pixel_format == FORMAT_BGRA) {
  44                 format = GL_BGRA;
  45                 bytes_per_pixel = 4;
  46         } else if (image_format.pixel_format == FORMAT_GRAYSCALE) {
  47                 format = GL_LUMINANCE;
  48                 bytes_per_pixel = 1;
  49         } else {
  50                 assert(false);
  51         }
  52
  53         // Create PBO to hold the texture holding the input image, and then the texture itself.
  54         glGenBuffers(1, &pbo);
  55         check_error();
  56         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
  57         check_error();
  58         glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, pitch * height * bytes_per_pixel, NULL, GL_STREAM_DRAW);
  59         check_error();
  60         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
  61         check_error();
  62
  63         glGenTextures(1, &texture_num);
  64         check_error();
  65         glBindTexture(GL_TEXTURE_2D, texture_num);
  66         check_error();
  67         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  68         check_error();
  69         glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch);
  70         check_error();
  71         // Intel/Mesa seems to have a broken glGenerateMipmap() for non-FBO textures, so do it here
  72         // instead of calling glGenerateMipmap().
  73         glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, needs_mipmaps);
  74         check_error();
  75         glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, NULL);
  76         check_error();
  77         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
  78         check_error();
  79
  80         needs_update = false;
  81         finalized = true;
  82 }
  83
  84 void FlatInput::set_gl_state(GLuint glsl_program_num, const std::string& prefix, unsigned *sampler_num)
  85 {
  86         glActiveTexture(GL_TEXTURE0 + *sampler_num);
  87         check_error();
  88         glBindTexture(GL_TEXTURE_2D, texture_num);
  89         check_error();
  90
  91         if (needs_update) {
  92                 // Copy the pixel data into the PBO.
  93                 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
  94                 check_error();
  95                 void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
  96                 memcpy(mapped_pbo, pixel_data, pitch * height * bytes_per_pixel);
  97                 glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
  98                 check_error();
  99
 100                 // Re-upload the texture from the PBO.
 101                 glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch);
 102                 check_error();
 103                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
 104                 check_error();
 105                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 106                 check_error();
 107                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 108                 check_error();
 109                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 110                 check_error();
 111                 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
 112                 check_error();
 113
 114                 needs_update = false;
 115         }
 116
 117         // Bind it to a sampler.
 118         set_uniform_int(glsl_program_num, prefix, "tex", *sampler_num);
 119         ++*sampler_num;
 120 }
 121
 122 std::string FlatInput::output_fragment_shader()
 123 {
 124         return read_file("flat_input.frag");
 125 }