fix refract

recp · Jul 15, 2024 · 48839a3 · 48839a3
1 parent d491108
commit 48839a3
Show file tree

Hide file tree

Showing 6 changed files with 9 additions and 9 deletions.
diff --git a/include/cglm/vec2.h b/include/cglm/vec2.h
@@ -749,7 +749,7 @@ glm_vec2_refract(vec2 v, vec2 n, float eta, vec2 dest) {
 
   ndi = glm_vec2_dot(n, v);
   eni = eta * ndi;
-  k   = 1.0f + eta * eta - eni * eni;
+  k   = 1.0f - eta * eta + eni * eni;
 
   if (k < 0.0f) {
     glm_vec2_zero(dest);

diff --git a/include/cglm/vec3.h b/include/cglm/vec3.h
@@ -1263,7 +1263,7 @@ glm_vec3_refract(vec3 v, vec3 n, float eta, vec3 dest) {
 
   ndi = glm_vec3_dot(n, v);
   eni = eta * ndi;
-  k   = 1.0f + eta * eta - eni * eni;
+  k   = 1.0f - eta * eta + eni * eni;
 
   if (k < 0.0f) {
     glm_vec3_zero(dest);

diff --git a/include/cglm/vec4.h b/include/cglm/vec4.h
@@ -1350,7 +1350,7 @@ glm_vec4_refract(vec4 v, vec4 n, float eta, vec4 dest) {
 
   ndi = glm_vec4_dot(n, v);
   eni = eta * ndi;
-  k   = 1.0f + eta * eta - eni * eni;
+  k   = 1.0f - eta * eta + eni * eni;
 
   if (k < 0.0f) {
     glm_vec4_zero(dest);

diff --git a/test/src/test_vec2.h b/test/src/test_vec2.h
@@ -792,7 +792,7 @@ TEST_IMPL(GLM_PREFIX, vec2_refract) {
   r = GLM(vec2_refract)(v, N, eta, dest);
   // In 2D, we expect a similar bending behavior as in 3D, so we check dest[1]
   if (!(dest[0] == 0.0f && dest[1] == 0.0f)) {
-    ASSERT(dest[1] < -sqrtf(0.5f)); // Refracted ray bends away from the normal
+    ASSERT(dest[1] < -0.3f); // Refracted ray bends away from the normal
     ASSERT(r == true);
   } else {
     ASSERT(dest[0] == 0.0f && dest[1] == 0.0f); // Total internal reflection
@@ -809,7 +809,7 @@ TEST_IMPL(GLM_PREFIX, vec2_refract) {
   eta = 1.5f / 1.33f;
   r = GLM(vec2_refract)(v, N, eta, dest);
   ASSERT(r == true);
-  ASSERT(dest[1] < -sqrtf(0.5f)); // Expect bending towards the normal, less bending than air to glass
+  ASSERT(dest[1] < -0.6f); // Expect bending towards the normal, less bending than air to glass
 
   /* Diamond to Air (eta = 2.42 / 1.0) */
   eta = 2.42f / 1.0f;

diff --git a/test/src/test_vec3.h b/test/src/test_vec3.h
@@ -1901,7 +1901,7 @@ TEST_IMPL(GLM_PREFIX, vec3_refract) {
   eta = 1.33f / 1.0f;
   r = GLM(vec3_refract)(v, N, eta, dest);
   if (!(dest[0] == 0.0f && dest[1] == 0.0f && dest[2] == 0.0f)) {
-    ASSERT(dest[1] < -sqrtf(0.5f));
+    ASSERT(dest[1] < -0.3f);
     ASSERT(r == true);
   } else {
     ASSERT(dest[0] == 0.0f && dest[1] == 0.0f && dest[2] == 0.0f);
@@ -1922,7 +1922,7 @@ TEST_IMPL(GLM_PREFIX, vec3_refract) {
 
   /* Expect bending towards the normal, less bending than air to glass */
   ASSERT(r == true);
-  ASSERT(dest[1] < -sqrtf(0.5f));
+  ASSERT(dest[1] < -0.6f);
 
   /* Diamond to Air (eta = 2.42 / 1.0) */
   eta = 2.42f / 1.0f;

diff --git a/test/src/test_vec4.h b/test/src/test_vec4.h
@@ -1586,7 +1586,7 @@ TEST_IMPL(GLM_PREFIX, vec4_refract) {
   eta = 1.33f / 1.0f;
   r = GLM(vec4_refract)(v, N, eta, dest);
   if (!(dest[0] == 0.0f && dest[1] == 0.0f && dest[2] == 0.0f && dest[3] == 0.0f)) {
-    ASSERT(dest[1] < -sqrtf(0.5f));
+    ASSERT(dest[1] < -0.3f);
     ASSERT(r == true);
   } else {
     ASSERT(dest[0] == 0.0f && dest[1] == 0.0f && dest[2] == 0.0f && dest[3] == 0.0f);
@@ -1603,7 +1603,7 @@ TEST_IMPL(GLM_PREFIX, vec4_refract) {
   eta = 1.5f / 1.33f;
   r = GLM(vec4_refract)(v, N, eta, dest);
   ASSERT(r == true);
-  ASSERT(dest[1] < -sqrtf(0.5f)); // Expect bending towards the normal, less bending than air to glass
+  ASSERT(dest[1] < -0.6f); // Expect bending towards the normal, less bending than air to glass
 
   /* Diamond to Air (eta = 2.42 / 1.0) */
   eta = 2.42f / 1.0f;