// Three-lobed Lanczos, the most common choice.
#define LANCZOS_RADIUS 3.0
-#include <math.h>
+#include <GL/glew.h>
#include <assert.h>
+#include <limits.h>
+#include <math.h>
+#include <stdio.h>
+#include <algorithm>
-#include "resample_effect.h"
#include "effect_chain.h"
+#include "effect_util.h"
+#include "resample_effect.h"
#include "util.h"
-#include "opengl.h"
namespace {
float offset, total_weight, sum_sq_error;
combine_two_samples(w1, w2, &offset, &total_weight, &sum_sq_error);
- // If the interpolation error is larger than that of one level
- // at 8-bit precision, don't combine.
- if (sum_sq_error > 1.0f / (256.0f * 256.0f)) {
+ // If the interpolation error is larger than that of about sqrt(2) of
+ // a level at 8-bit precision, don't combine. (You'd think 1.0 was enough,
+ // but since the artifacts are not really random, they can get quite
+ // visible. On the other hand, going to 0.25f, I can see no change at
+ // all with 8-bit output, so it would not seem to be worth it.)
+ if (sum_sq_error > 0.5f / (256.0f * 256.0f)) {
continue;
}
// The first blur pass will forward resolution information to us.
hpass = new SingleResamplePassEffect(this);
- hpass->set_int("direction", SingleResamplePassEffect::HORIZONTAL);
+ CHECK(hpass->set_int("direction", SingleResamplePassEffect::HORIZONTAL));
vpass = new SingleResamplePassEffect(NULL);
- vpass->set_int("direction", SingleResamplePassEffect::VERTICAL);
+ CHECK(vpass->set_int("direction", SingleResamplePassEffect::VERTICAL));
update_size();
}
// so out[0] will read from parameters <x,y> = <0,0>, <1,0>, <2,0> and so on.
//
// For horizontal scaling, we fill in the exact same texture;
-// the shader just interprets is differently.
+// the shader just interprets it differently.
void SingleResamplePassEffect::update_texture(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num)
{
unsigned src_size, dst_size;
{
Effect::set_gl_state(glsl_program_num, prefix, sampler_num);
+ assert(input_width > 0);
+ assert(input_height > 0);
+ assert(output_width > 0);
+ assert(output_height > 0);
+
if (input_width != last_input_width ||
input_height != last_input_height ||
output_width != last_output_width ||