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 }
  33
  34 string PaddingEffect::output_fragment_shader()
  35 {
  36         return read_file("padding_effect.frag");
  37 }
  38
  39 void PaddingEffect::set_gl_state(GLuint glsl_program_num, const string &prefix, unsigned *sampler_num)
  40 {
  41         Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
  42
  43         float offset[2] = {
  44                 left / output_width,
  45                 (output_height - input_height - top) / output_height
  46         };
  47         set_uniform_vec2(glsl_program_num, prefix, "offset", offset);
  48
  49         float scale[2] = {
  50                 float(output_width) / input_width,
  51                 float(output_height) / input_height
  52         };
  53         set_uniform_vec2(glsl_program_num, prefix, "scale", scale);
  54
  55         float normalized_coords_to_texels[2] = {
  56                 float(input_width), float(input_height)
  57         };
  58         set_uniform_vec2(glsl_program_num, prefix, "normalized_coords_to_texels", normalized_coords_to_texels);
  59
  60         // Texels -0.5..0.5 should map to light level 0..1 (and then we
  61         // clamp the rest).
  62         float offset_bottomleft[2] = {
  63                 0.5f - border_offset_left, 0.5f + border_offset_bottom,
  64         };
  65
  66         // Texels size-0.5..size+0.5 should map to light level 1..0 (and then clamp).
  67         float offset_topright[2] = {
  68                 input_width + 0.5f + border_offset_right, input_height + 0.5f - border_offset_top,
  69         };
  70
  71         set_uniform_vec2(glsl_program_num, prefix, "offset_bottomleft", offset_bottomleft);
  72         set_uniform_vec2(glsl_program_num, prefix, "offset_topright", offset_topright);
  73 }
  74
  75 // We don't change the pixels of the image itself, so the only thing that
  76 // can make us less flexible is if the border color can be interpreted
  77 // differently in different modes.
  78
  79 // 0.0 and 1.0 are interpreted the same, no matter the gamma ramp.
  80 // Alpha is not affected by gamma per se, but the combination of
  81 // premultiplied alpha and non-linear gamma curve does not make sense,
  82 // so if could possibly be converting blank alpha to non-blank
  83 // (ie., premultiplied), we need our output to be in linear light.
  84 bool PaddingEffect::needs_linear_light() const
  85 {
  86         if ((border_color.r == 0.0 || border_color.r == 1.0) &&
  87             (border_color.g == 0.0 || border_color.g == 1.0) &&
  88             (border_color.b == 0.0 || border_color.b == 1.0) &&
  89             border_color.a == 1.0) {
  90                 return false;
  91         }
  92         return true;
  93 }
  94
  95 // The white point is the same (D65) in all the color spaces we currently support,
  96 // so any gray would be okay, but we don't really have a guarantee for that.
  97 // Stay safe and say that only pure black and pure white is okay.
  98 // Alpha is not affected by color space.
  99 bool PaddingEffect::needs_srgb_primaries() const
 100 {
 101         if (border_color.r == 0.0 && border_color.g == 0.0 && border_color.b == 0.0) {
 102                 return false;
 103         }
 104         if (border_color.r == 1.0 && border_color.g == 1.0 && border_color.b == 1.0) {
 105                 return false;
 106         }
 107         return true;
 108 }
 109
 110 Effect::AlphaHandling PaddingEffect::alpha_handling() const
 111 {
 112         // If the border color is black, it doesn't matter if we're pre- or postmultiplied.
 113         // Note that for non-solid black (i.e. alpha < 1.0), we're equally fine with
 114         // pre- and postmultiplied, but later effects might change this status
 115         // (consider e.g. blur), so setting DONT_CARE_ALPHA_TYPE is inappropriate,
 116         // as it propagate blank alpha through this effect.
 117         if (border_color.r == 0.0 && border_color.g == 0.0 && border_color.b == 0.0 && border_color.a == 1.0) {
 118                 return DONT_CARE_ALPHA_TYPE;
 119         }
 120
 121         // If the border color is solid, we preserve blank alpha, as we never output any
 122         // new non-solid pixels.
 123         if (border_color.a == 1.0) {
 124                 return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK;
 125         }
 126
 127         // Otherwise, we're going to output our border color in premultiplied alpha,
 128         // so the other pixels better be premultiplied as well.
 129         return INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA;
 130 }
 131
 132 void PaddingEffect::get_output_size(unsigned *width, unsigned *height, unsigned *virtual_width, unsigned *virtual_height) const
 133 {
 134         *virtual_width = *width = output_width;
 135         *virtual_height = *height = output_height;
 136 }
 137
 138 void PaddingEffect::inform_input_size(unsigned input_num, unsigned width, unsigned height)
 139 {
 140         assert(input_num == 0);
 141         input_width = width;
 142         input_height = height;
 143 }
 144
 145 IntegralPaddingEffect::IntegralPaddingEffect() {}
 146
 147 bool IntegralPaddingEffect::set_int(const std::string &key, int value)
 148 {
 149         if (key == "top" || key == "left") {
 150                 return PaddingEffect::set_float(key, value);
 151         } else {
 152                 return PaddingEffect::set_int(key, value);
 153         }
 154 }
 155
 156 bool IntegralPaddingEffect::set_float(const std::string &key, float value)
 157 {
 158         if (key == "top" || key == "left") {
 159                 // These are removed as float parameters from this version.
 160                 return false;
 161         } else {
 162                 return PaddingEffect::set_float(key, value);
 163         }
 164 }
 165
 166 }  // namespace movit