From 7c4bbdc3983da3ef32fb09ad0491c63a0a4ca1d7 Mon Sep 17 00:00:00 2001
From: Jelle Raaijmakers <jelle@gmta.nl>
Date: Sat, 26 Nov 2022 10:50:27 +0100
Subject: [PATCH] LibGL: Simplify transposing input matrices

We do not need to templatize the output type - it's always `float`.
Also, the input type can be inferred. Finally, use template
specialization instead of a conditional to deal with same type input and
output matrices.
---
 Userland/Libraries/LibGL/GLAPI.cpp | 40 ++++++++++++++++--------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/Userland/Libraries/LibGL/GLAPI.cpp b/Userland/Libraries/LibGL/GLAPI.cpp
index 293d18e900..c33704af55 100644
--- a/Userland/Libraries/LibGL/GLAPI.cpp
+++ b/Userland/Libraries/LibGL/GLAPI.cpp
@@ -15,23 +15,12 @@
 extern GL::GLContext* g_gl_context;
 
 // Transposes input matrices (column-major) to our Matrix (row-major).
-template<typename I, typename O>
-static constexpr Matrix4x4<O> transpose_input_matrix(I const* matrix)
+template<typename I>
+constexpr FloatMatrix4x4 transpose_input_matrix(I const* matrix)
 {
-    if constexpr (IsSame<I, O>) {
-        // clang-format off
-        return {
-            matrix[0], matrix[4], matrix[8], matrix[12],
-            matrix[1], matrix[5], matrix[9], matrix[13],
-            matrix[2], matrix[6], matrix[10], matrix[14],
-            matrix[3], matrix[7], matrix[11], matrix[15],
-        };
-        // clang-format on
-    }
-
-    Array<O, 16> elements;
+    Array<float, 16> elements;
     for (size_t i = 0; i < 16; ++i)
-        elements[i] = static_cast<O>(matrix[i]);
+        elements[i] = static_cast<float>(matrix[i]);
     // clang-format off
     return {
         elements[0], elements[4], elements[8], elements[12],
@@ -42,6 +31,19 @@ static constexpr Matrix4x4<O> transpose_input_matrix(I const* matrix)
     // clang-format on
 }
 
+template<>
+constexpr FloatMatrix4x4 transpose_input_matrix(float const* matrix)
+{
+    // clang-format off
+    return {
+        matrix[0], matrix[4], matrix[8], matrix[12],
+        matrix[1], matrix[5], matrix[9], matrix[13],
+        matrix[2], matrix[6], matrix[10], matrix[14],
+        matrix[3], matrix[7], matrix[11], matrix[15],
+    };
+    // clang-format on
+}
+
 void glActiveTexture(GLenum texture)
 {
     g_gl_context->gl_active_texture(texture);
@@ -620,12 +622,12 @@ void glLoadIdentity()
 
 void glLoadMatrixd(GLdouble const* matrix)
 {
-    g_gl_context->gl_load_matrix(transpose_input_matrix<double, float>(matrix));
+    g_gl_context->gl_load_matrix(transpose_input_matrix(matrix));
 }
 
 void glLoadMatrixf(GLfloat const* matrix)
 {
-    g_gl_context->gl_load_matrix(transpose_input_matrix<float, float>(matrix));
+    g_gl_context->gl_load_matrix(transpose_input_matrix(matrix));
 }
 
 void glMap1d(GLenum target, GLdouble u1, GLdouble u2, GLint stride, GLint order, GLdouble const* points)
@@ -738,12 +740,12 @@ void glMultiTexCoord4f(GLenum target, GLfloat s, GLfloat t, GLfloat r, GLfloat q
 
 void glMultMatrixd(GLdouble const* matrix)
 {
-    g_gl_context->gl_mult_matrix(transpose_input_matrix<double, float>(matrix));
+    g_gl_context->gl_mult_matrix(transpose_input_matrix(matrix));
 }
 
 void glMultMatrixf(GLfloat const* matrix)
 {
-    g_gl_context->gl_mult_matrix(transpose_input_matrix<float, float>(matrix));
+    g_gl_context->gl_mult_matrix(transpose_input_matrix(matrix));
 }
 
 void glNewList(GLuint list, GLenum mode)