From 08128c14ec49a2b357e830c832ccd0a8e63c175d Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 14 Jan 2024 11:38:09 +0000
Subject: Add traits wrapper for setting uniforms

---
 lib/gl_traits.h | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

(limited to 'lib')

diff --git a/lib/gl_traits.h b/lib/gl_traits.h
index 934b505..2d3d85d 100644
--- a/lib/gl_traits.h
+++ b/lib/gl_traits.h
@@ -4,6 +4,8 @@
 #include <glad/gl.h>
 #include <glm/common.hpp>
 #include <glm/fwd.hpp>
+#include <glm/gtc/type_ptr.hpp>
+#include <span>
 
 template<typename T> struct gl_traits;
 
@@ -37,6 +39,9 @@ struct gl_traits_integer : public gl_traits_base {
 
 template<> struct gl_traits<glm::f32> : public gl_traits_float {
 	static constexpr GLenum type {GL_FLOAT};
+	static constexpr auto glUniformFunc {&glUniform1f};
+	static constexpr std::array glUniformvFunc {&glUniform1fv, &glUniform2fv, &glUniform3fv, &glUniform4fv};
+	static constexpr std::array glUniformmFunc {&glUniformMatrix2fv, &glUniformMatrix3fv, &glUniformMatrix4fv};
 };
 
 template<> struct gl_traits<glm::f64> : public gl_traits_longfloat {
@@ -53,6 +58,8 @@ template<> struct gl_traits<glm::int16> : public gl_traits_integer {
 
 template<> struct gl_traits<glm::int32> : public gl_traits_integer {
 	static constexpr GLenum type {GL_INT};
+	static constexpr auto glUniformFunc {&glUniform1i};
+	static constexpr std::array glUniformvFunc {&glUniform1iv, &glUniform2iv, &glUniform3iv, &glUniform4iv};
 };
 
 template<> struct gl_traits<glm::uint8> : public gl_traits_integer {
@@ -65,6 +72,9 @@ template<> struct gl_traits<glm::uint16> : public gl_traits_integer {
 
 template<> struct gl_traits<glm::uint32> : public gl_traits_integer {
 	static constexpr GLenum type {GL_UNSIGNED_INT};
+	static constexpr auto glUniformFunc {&glUniform1ui};
+	static constexpr std::array<decltype(&glUniform1uiv), 5> glUniformvFunc {
+			&glUniform1uiv, &glUniform2uiv, &glUniform3uiv, &glUniform4uiv};
 };
 
 template<typename T, std::size_t S> struct gl_traits<std::array<T, S>> : public gl_traits<T> {
@@ -87,3 +97,49 @@ struct gl_traits<glm::mat<C, R, T, Q>> : public gl_traits<T> {
 				return R;
 			}};
 };
+
+template<typename T>
+void
+glUniform(GLint location, T v)
+{
+	static_assert(
+			requires { gl_traits<T>::glUniformFunc; }, "Has glUnform1T");
+	(*gl_traits<T>::glUniformFunc)(location, v);
+}
+
+template<glm::length_t L, typename T, glm::qualifier Q>
+void
+glUniform(GLint location, const glm::vec<L, T, Q> & v)
+{
+	static_assert(
+			requires { gl_traits<T>::glUniformFunc; }, "Has glUnformNTv");
+	(*gl_traits<T>::glUniformvFunc[L - 1])(location, 1, glm::value_ptr(v));
+}
+
+template<glm::length_t L, typename T, glm::qualifier Q>
+void
+glUniform(GLint location, std::span<const glm::vec<L, T, Q>> v)
+{
+	static_assert(
+			requires { gl_traits<T>::glUniformvFunc; }, "Has glUnformNTv");
+	(*gl_traits<T>::glUniformvFunc[L - 1])(location, static_cast<GLsizei>(v.size()), glm::value_ptr(v.front()));
+}
+
+template<glm::length_t L, typename T, glm::qualifier Q>
+void
+glUniform(GLint location, const glm::mat<L, L, T, Q> & v)
+{
+	static_assert(
+			requires { gl_traits<T>::glUniformmFunc; }, "Has glUnformMatrixNTv");
+	(*gl_traits<T>::glUniformmFunc[L - 2])(location, 1, GL_FALSE, glm::value_ptr(v));
+}
+
+template<glm::length_t L, typename T, glm::qualifier Q>
+void
+glUniform(GLint location, std::span<const glm::mat<L, L, T, Q>> v)
+{
+	static_assert(
+			requires { gl_traits<T>::glUniformmFunc; }, "Has glUnformMatrixNTv");
+	(*gl_traits<T>::glUniformmFunc[L - 2])(
+			location, static_cast<GLsizei>(v.size()), GL_FALSE, glm::value_ptr(v.front()));
+}
-- 
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