X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=resample_effect.cpp;h=c2ef531d3dee6b9fa272bebfe2f97086ce23126a;hp=e1e6199ec5b5b857add0df623d6fd05a25d4b1e0;hb=18fdebc534adc6b7a4c36b290b01d598bcb671bc;hpb=9447b2d234394c1d966f77ed87271a3625a81cdd

diff --git a/resample_effect.cpp b/resample_effect.cpp
index e1e6199..c2ef531 100644
--- a/resample_effect.cpp
+++ b/resample_effect.cpp
@@ -1,13 +1,17 @@
 // 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 {
 
@@ -74,9 +78,12 @@ unsigned combine_samples(float *src, float *dst, unsigned num_src_samples, unsig
 		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;
 		}
 
@@ -204,7 +211,7 @@ std::string SingleResamplePassEffect::output_fragment_shader()
 // 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;
@@ -345,6 +352,11 @@ void SingleResamplePassEffect::set_gl_state(GLuint glsl_program_num, const std::
 {
 	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 ||