X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=util.h;h=8cabaf7c3eafe8be36928521bb324545521325ba;hp=f57af77691befa0afa80bb943f7d11a6e54aeadd;hb=7cfa62b39fb56fb1e5f094fa11bfe9d84445c80f;hpb=d88ed3150376693000665b9016c0350d5d90e9e1

diff --git a/util.h b/util.h
index f57af77..8cabaf7 100644
--- a/util.h
+++ b/util.h
@@ -38,7 +38,8 @@ 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);
 
-// Output GLSL 2-length and 3-length vector declarations.
+// Output GLSL scalar, 2-length and 3-length vector declarations.
+std::string output_glsl_float(const std::string &name, float x);
 std::string output_glsl_vec2(const std::string &name, float x, float y);
 std::string output_glsl_vec3(const std::string &name, float x, float y, float z);
 
@@ -53,8 +54,11 @@ enum CombineRoundingBehavior {
 // Calculate where to sample, and with what weight, if one wants to use
 // the GPU's bilinear hardware to sample w1 * x[pos1] + w2 * x[pos2],
 // where pos1 and pos2 must be normalized coordinates describing neighboring
-// pixels in the mipmap level at which you sample, and the total number of
-// pixels (in given mipmap level) is <size>.
+// texels in the mipmap level at which you sample. <num_subtexels> is the
+// number of distinct accessible subtexels in the given mipmap level,
+// calculated by num_texels / movit_texel_subpixel_precision. It is a float
+// for performance reasons, even though it is expected to be a whole number.
+// <inv_num_subtexels> is simply its inverse (1/x).
 //
 // Note that since the GPU might have limited precision in its linear
 // interpolation, the effective weights might be different from the ones you
@@ -67,7 +71,7 @@ enum CombineRoundingBehavior {
 // rounded fp16 value. This enables more precise calculation of total_weight
 // and sum_sq_error.
 template<class DestFloat>
-void combine_two_samples(float w1, float w2, float pos1, float pos2, unsigned size,
+void combine_two_samples(float w1, float w2, float pos1, float pos2, float num_subtexels, float inv_num_subtexels,
                          DestFloat *offset, DestFloat *total_weight, float *sum_sq_error);
 
 // Create a VBO with the given data, and bind it to the vertex attribute