float w2 = weight[base_pos + 1];
float offset, total_weight;
- if (w1 + w2 < 1e-6) {
- offset = 0.5f;
- total_weight = 0.0f;
- } else {
- offset = w2 / (w1 + w2);
- total_weight = w1 + w2;
- }
+ combine_two_samples(w1, w2, &offset, &total_weight);
+
float x = 0.0f, y = 0.0f;
if (direction == HORIZONTAL) {
// 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()
#else