X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=util.h;h=432171ac015d3fd5921b5eb9fe9c0ccffd92b9b3;hb=1a06994ccdeedba95a1bdd2c3c12bb54a7a897f9;hp=1c2f6a669f6bec63d9a4531c9b3c57986ae70c8c;hpb=96a1cff51a8b7dc45ebe725e0d0685eecce31331;p=movit

diff --git a/util.h b/util.h
index 1c2f6a6..432171a 100644
--- a/util.h
+++ b/util.h
@@ -1,24 +1,54 @@
 #ifndef _UTIL_H
 #define _UTIL_H 1
 
+// Various utilities.
+
 #include <stdio.h>
 #include <stdlib.h>
 
 #include <string>
+#include <Eigen/Core>
+
+#include "opengl.h"
 
-#include <GL/gl.h>
+#define BUFFER_OFFSET(i) ((char *)NULL + (i))
 
-// assumes h in [0, 2pi> or [-pi, pi>
+// Converts a HSV color to RGB. Assumes h in [0, 2pi> or [-pi, pi>
 void hsv2rgb(float h, float s, float v, float *r, float *g, float *b);
 
-// Column major (same as OpenGL).
-typedef double Matrix3x3[9];
+// Converts a HSV color to RGB, but keeps luminance constant
+// (ie. color luminance is as if S=0).
+void hsv2rgb_normalized(float h, float s, float v, float *r, float *g, float *b);
 
+// Read a file from disk and return its contents.
+// Dies if the file does not exist.
 std::string read_file(const std::string &filename);
+
+// Compile the given GLSL shader (typically a vertex or fragment shader)
+// and return the object number.
 GLuint compile_shader(const std::string &shader_src, GLenum type);
-void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
-void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result);
-void print_3x3_matrix(const Matrix3x3 m);
+
+// Print a 3x3 matrix to standard output. Useful for debugging.
+void print_3x3_matrix(const Eigen::Matrix3d &m);
+
+// Output a GLSL 3x3 matrix declaration.
+std::string output_glsl_mat3(const std::string &name, const Eigen::Matrix3d &m);
+
+// Calculate where to sample, and with what weight, if one wants to use
+// the GPU's bilinear hardware to sample w1 * x[0] + w2 * x[1].
+static inline void combine_two_samples(float w1, float w2, float *offset, float *total_weight)
+{
+	assert(w1 * w2 >= 0.0f);  // Should not have differing signs.
+	if (fabs(w1 + w2) < 1e-6) {
+		*offset = 0.5f;
+		*total_weight = 0.0f;
+	} else {
+		*offset = w2 / (w1 + w2);
+		*total_weight = w1 + w2;
+	}
+	assert(*offset >= 0.0f);
+	assert(*offset <= 1.0f);
+}
 
 #ifdef NDEBUG
 #define check_error()