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

   1 #include <epoxy/gl.h>
   2 #include <assert.h>
   3
   4 #include "effect_util.h"
   5 #include "padding_effect.h"
   6 #include "util.h"
   7
   8 using namespace std;
   9
  10 namespace movit {
  11
  12 PaddingEffect::PaddingEffect()
  13         : border_color(0.0f, 0.0f, 0.0f, 0.0f),
  14           output_width(1280),
  15           output_height(720),
  16           top(0),
  17           left(0),
  18           border_offset_top(0.0f),
  19           border_offset_left(0.0f),
  20           border_offset_bottom(0.0f),
  21           border_offset_right(0.0f)
  22 {
  23         register_vec4("border_color", (float *)&border_color);
  24         register_int("width", &output_width);
  25         register_int("height", &output_height);
  26         register_float("top", &top);
  27         register_float("left", &left);
  28         register_float("border_offset_top", &border_offset_top);
  29         register_float("border_offset_left", &border_offset_left);
  30         register_float("border_offset_bottom", &border_offset_bottom);
  31         register_float("border_offset_right", &border_offset_right);
  32         register_uniform_vec2("offset", uniform_offset);
  33         register_uniform_vec2("scale", uniform_scale);
  34         register_uniform_vec2("normalized_coords_to_texels", uniform_normalized_coords_to_texels);
  35         register_uniform_vec2("offset_bottomleft", uniform_offset_bottomleft);
  36         register_uniform_vec2("offset_topright", uniform_offset_topright);
  37 }
  38
  39 string PaddingEffect::output_fragment_shader()
  40 {
  41         return read_file("padding_effect.frag");
  42 }
  43
  44 void PaddingEffect::set_gl_state(GLuint glsl_program_num, const string &prefix, unsigned *sampler_num)
  45 {
  46         Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
  47
  48         uniform_offset[0] = left / output_width;
  49         uniform_offset[1] = (output_height - input_height - top) / output_height;
  50
  51         uniform_scale[0] = float(output_width) / input_width;
  52         uniform_scale[1] = float(output_height) / input_height;
  53
  54         uniform_normalized_coords_to_texels[0] = float(input_width);
  55         uniform_normalized_coords_to_texels[1] = float(input_height);
  56
  57         // Texels -0.5..0.5 should map to light level 0..1 (and then we
  58         // clamp the rest).
  59         uniform_offset_bottomleft[0] = 0.5f - border_offset_left;
  60         uniform_offset_bottomleft[1] = 0.5f + border_offset_bottom;
  61
  62         // Texels size-0.5..size+0.5 should map to light level 1..0 (and then clamp).
  63         uniform_offset_topright[0] = input_width + 0.5f + border_offset_right;
  64         uniform_offset_topright[1] = input_height + 0.5f - border_offset_top;
  65 }
  66
  67 // We don't change the pixels of the image itself, so the only thing that
  68 // can make us less flexible is if the border color can be interpreted
  69 // differently in different modes.
  70
  71 // 0.0 and 1.0 are interpreted the same, no matter the gamma ramp.
  72 // Alpha is not affected by gamma per se, but the combination of
  73 // premultiplied alpha and non-linear gamma curve does not make sense,
  74 // so if could possibly be converting blank alpha to non-blank
  75 // (ie., premultiplied), we need our output to be in linear light.
  76 bool PaddingEffect::needs_linear_light() const
  77 {
  78         if ((border_color.r == 0.0 || border_color.r == 1.0) &&
  79             (border_color.g == 0.0 || border_color.g == 1.0) &&
  80             (border_color.b == 0.0 || border_color.b == 1.0) &&
  81             border_color.a == 1.0) {
  82                 return false;
  83         }
  84         return true;
  85 }
  86
  87 // The white point is the same (D65) in all the color spaces we currently support,
  88 // so any gray would be okay, but we don't really have a guarantee for that.
  89 // Stay safe and say that only pure black and pure white is okay.
  90 // Alpha is not affected by color space.
  91 bool PaddingEffect::needs_srgb_primaries() const
  92 {
  93         if (border_color.r == 0.0 && border_color.g == 0.0 && border_color.b == 0.0) {
  94                 return false;
  95         }
  96         if (border_color.r == 1.0 && border_color.g == 1.0 && border_color.b == 1.0) {
  97                 return false;
  98         }
  99         return true;
 100 }
 101
 102 Effect::AlphaHandling PaddingEffect::alpha_handling() const
 103 {
 104         // If the border color is solid, it doesn't matter if we're pre- or postmultiplied.
 105         if (border_color.a == 1.0) {
 106                 return DONT_CARE_ALPHA_TYPE;
 107         }
 108
 109         // Otherwise, we're going to output our border color in premultiplied alpha,
 110         // so the other pixels better be premultiplied as well.
 111         // Note that for non-solid black (i.e. alpha < 1.0), we're equally fine with
 112         // pre- and postmultiplied, but we are _not_ fine with blank being passed through,
 113         // and we don't have a way to specify that.
 114         return INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA;
 115 }
 116
 117 void PaddingEffect::get_output_size(unsigned *width, unsigned *height, unsigned *virtual_width, unsigned *virtual_height) const
 118 {
 119         *virtual_width = *width = output_width;
 120         *virtual_height = *height = output_height;
 121 }
 122
 123 void PaddingEffect::inform_input_size(unsigned input_num, unsigned width, unsigned height)
 124 {
 125         assert(input_num == 0);
 126         input_width = width;
 127         input_height = height;
 128 }
 129
 130 IntegralPaddingEffect::IntegralPaddingEffect() {}
 131
 132 bool IntegralPaddingEffect::set_int(const std::string &key, int value)
 133 {
 134         if (key == "top" || key == "left") {
 135                 return PaddingEffect::set_float(key, value);
 136         } else {
 137                 return PaddingEffect::set_int(key, value);
 138         }
 139 }
 140
 141 bool IntegralPaddingEffect::set_float(const std::string &key, float value)
 142 {
 143         if (key == "top" || key == "left") {
 144                 // These are removed as float parameters from this version.
 145                 return false;
 146         } else {
 147                 return PaddingEffect::set_float(key, value);
 148         }
 149 }
 150
 151 }  // namespace movit