-#include <math.h>
#include <GL/glew.h>
+#include <assert.h>
+#include "effect_util.h"
#include "padding_effect.h"
#include "util.h"
// than losing a pixel in the common cases of integer shift.
// Thus the 1e-3 fudge factors.
float texcoord_min[2] = {
- (0.5f - 1e-3) / input_width,
- (0.5f - 1e-3) / input_height
+ float((0.5f - 1e-3) / input_width),
+ float((0.5f - 1e-3) / input_height)
};
set_uniform_vec2(glsl_program_num, prefix, "texcoord_min", texcoord_min);
float texcoord_max[2] = {
- 1.0f - (0.5f - 1e-3) / input_width,
- 1.0f - (0.5f - 1e-3) / input_height
+ float(1.0f - (0.5f - 1e-3) / input_width),
+ float(1.0f - (0.5f - 1e-3) / input_height)
};
set_uniform_vec2(glsl_program_num, prefix, "texcoord_max", texcoord_max);
}
return true;
}
-// If the border color is black, it doesn't matter if we're pre- or postmultiplied
-// (or even blank, as a hack). Otherwise, it does.
Effect::AlphaHandling PaddingEffect::alpha_handling() const
{
- if (border_color.r == 0.0 && border_color.g == 0.0 && border_color.b == 0.0) {
+ // If the border color is black, it doesn't matter if we're pre- or postmultiplied.
+ // Note that for non-solid black (i.e. alpha < 1.0), we're equally fine with
+ // pre- and postmultiplied, but later effects might change this status
+ // (consider e.g. blur), so setting DONT_CARE_ALPHA_TYPE is inappropriate,
+ // as it propagate blank alpha through this effect.
+ if (border_color.r == 0.0 && border_color.g == 0.0 && border_color.b == 0.0 && border_color.a == 1.0) {
return DONT_CARE_ALPHA_TYPE;
}
- return INPUT_AND_OUTPUT_ALPHA_PREMULTIPLIED;
+
+ // If the border color is solid, we preserve blank alpha, as we never output any
+ // new non-solid pixels.
+ if (border_color.a == 1.0) {
+ return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK;
+ }
+
+ // Otherwise, we're going to output our border color in premultiplied alpha,
+ // so the other pixels better be premultiplied as well.
+ return INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA;
}
-void PaddingEffect::get_output_size(unsigned *width, unsigned *height) const
+void PaddingEffect::get_output_size(unsigned *width, unsigned *height, unsigned *virtual_width, unsigned *virtual_height) const
{
- *width = output_width;
- *height = output_height;
+ *virtual_width = *width = output_width;
+ *virtual_height = *height = output_height;
}
void PaddingEffect::inform_input_size(unsigned input_num, unsigned width, unsigned height)