X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=blur_effect.cpp;h=17044f12f35c54681148814f38efebac4d37f5e0;hp=e945295da641dd565c74b54684be93e158de0022;hb=0c1fab7813e12580bed0852d9e57b0a3f2768d83;hpb=b5e3174594efe9a920621a68d3b28f5e44676d03

diff --git a/blur_effect.cpp b/blur_effect.cpp
index e945295..17044f1 100644
--- a/blur_effect.cpp
+++ b/blur_effect.cpp
@@ -3,14 +3,17 @@
 #include <math.h>
 #include <GL/gl.h>
 #include <GL/glext.h>
+#include <assert.h>
 
 #include "blur_effect.h"
 #include "util.h"
 
 BlurEffect::BlurEffect()
-	: radius(0.3f)
+	: radius(3.0f),
+	  direction(HORIZONTAL)
 {
 	register_float("radius", (float *)&radius);
+	register_int("direction", (int *)&direction);
 }
 
 std::string BlurEffect::output_fragment_shader()
@@ -21,4 +24,55 @@ std::string BlurEffect::output_fragment_shader()
 void BlurEffect::set_uniforms(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num)
 {
 	Effect::set_uniforms(glsl_program_num, prefix, sampler_num);
+
+	// We only have 15 taps to work with, and we want that to reach out to about 2.5*sigma.
+	// Bump up the mipmap levels (giving us box blurs) until we have what we need.
+	unsigned base_mipmap_level = 0;
+	float adjusted_radius = radius;
+	float pixel_size = 1.0f;
+	while (adjusted_radius * 2.5f > 7.0f) {
+		++base_mipmap_level;
+		adjusted_radius *= 0.5f;
+		pixel_size *= 2.0f;
+	}	
+
+	// In the second pass, we do the same, but don't sample from a mipmap;
+	// that would re-blur the other direction in an ugly fashion, and we already
+	// have the vertical box blur we need from that pass.
+	//
+	// TODO: We really need to present horizontal+vertical as a unit;
+	// currently, there's really no guarantee vertical blur is the second pass.
+	if (direction == VERTICAL) {
+		base_mipmap_level = 0;
+	}
+
+	glActiveTexture(GL_TEXTURE0);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, base_mipmap_level);
+	check_error();
+
+	// FIXME
+	if (direction == HORIZONTAL) {
+		float ps[] = { pixel_size / 1280.0f, 0.0f };
+		set_uniform_vec2(glsl_program_num, prefix, "pixel_offset", ps);
+	} else if (direction == VERTICAL) {
+		float ps[] = { 0.0f, pixel_size / 720.0f };
+		set_uniform_vec2(glsl_program_num, prefix, "pixel_offset", ps);
+	} else {
+		assert(false);
+	}
+
+	// Simple Gaussian weights for now.
+	float weight[15], total = 0.0f;
+	for (unsigned i = 0; i < 15; ++i) {
+		float z = (i - 7.0f) / adjusted_radius;
+		weight[i] = exp(-(z*z));
+		total += weight[i];
+	}
+	printf("[mip level %d] ", base_mipmap_level);
+	for (unsigned i = 0; i < 15; ++i) {
+		weight[i] /= total;
+		printf("%f ", weight[i]);
+	}
+	printf("\n");
+	set_uniform_float_array(glsl_program_num, prefix, "weight", weight, 15);
 }