Scalar multiplication

glm/gtx/rotate_vector.inl

@@ -25,7 +25,7 @@ namespace glm
 		T SinAlpha = sin(Alpha);
 		// this breaks down when SinAlpha = 0, i.e. Alpha = 0 or pi
 		T t1 = sin((static_cast<T>(1) - a) * Alpha) / SinAlpha;
-		T t2 = sin(a * Alpha) / sinAlpha;
+		T t2 = sin(a * Alpha) / SinAlpha;
 
 		// interpolate src vectors
 		return x * t1 + y * t2;

glm/gtx/scalar_multiplication.hpp

@@ -0,0 +1,91 @@
+///////////////////////////////////////////////////////////////////////////////////
+/// OpenGL Mathematics (glm.g-truc.net)
+///
+/// Copyright (c) 2005 - 2014 G-Truc Creation (www.g-truc.net)
+/// Permission is hereby granted, free of charge, to any person obtaining a copy
+/// of this software and associated documentation files (the "Software"), to deal
+/// in the Software without restriction, including without limitation the rights
+/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+/// copies of the Software, and to permit persons to whom the Software is
+/// furnished to do so, subject to the following conditions:
+///
+/// The above copyright notice and this permission notice shall be included in
+/// all copies or substantial portions of the Software.
+///
+/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+/// THE SOFTWARE.
+///
+/// @ref gtx
+/// @file glm/gtx/scalar_multiplication.hpp
+/// @date 2014-09-22 / 2014-09-22
+/// @author Joshua Moerman
+///
+/// @brief Enables scalar multiplication for all types
+///
+/// Since GLSL is very strict about types, the following (often used) combinations do not work:
+///    double * vec4
+///    int * vec4
+///    vec4 / int
+/// So we'll fix that! Of course "float * vec4" should remain the same (hence the enable_if magic)
+///
+///////////////////////////////////////////////////////////////////////////////////
+
+#pragma once
+
+#include "../vec2.hpp"
+#include "../vec3.hpp"
+#include "../vec4.hpp"
+#include "../mat2x2.hpp"
+#include <type_traits>
+
+namespace glm{
+namespace detail
+{
+	template <typename T, typename Vec>
+	using return_type_scalar_multiplication = typename std::enable_if<
+		!std::is_same<T, float>::value       // T may not be a float
+		&& std::is_arithmetic<T>::value, Vec // But it may be an int or double (no vec3 or mat3, ...)
+	>::type;
+
+#define GLM_IMPLEMENT_SCAL_MULT(Vec) \
+	template <typename T> \
+	return_type_scalar_multiplication<T, Vec> \
+	operator*(T const & s, Vec rh){ \
+		return rh *= static_cast<float>(s); \
+	} \
+	 \
+	template <typename T> \
+	return_type_scalar_multiplication<T, Vec> \
+	operator*(Vec lh, T const & s){ \
+		return lh *= static_cast<float>(s); \
+	} \
+	 \
+	template <typename T> \
+	return_type_scalar_multiplication<T, Vec> \
+	operator/(Vec lh, T const & s){ \
+		return lh *= 1.0f / s; \
+	}
+
+GLM_IMPLEMENT_SCAL_MULT(vec2)
+GLM_IMPLEMENT_SCAL_MULT(vec3)
+GLM_IMPLEMENT_SCAL_MULT(vec4)
+
+GLM_IMPLEMENT_SCAL_MULT(mat2)
+GLM_IMPLEMENT_SCAL_MULT(mat2x3)
+GLM_IMPLEMENT_SCAL_MULT(mat2x4)
+GLM_IMPLEMENT_SCAL_MULT(mat3x2)
+GLM_IMPLEMENT_SCAL_MULT(mat3)
+GLM_IMPLEMENT_SCAL_MULT(mat3x4)
+GLM_IMPLEMENT_SCAL_MULT(mat4x2)
+GLM_IMPLEMENT_SCAL_MULT(mat4x3)
+GLM_IMPLEMENT_SCAL_MULT(mat4)
+
+#undef GLM_IMPLEMENT_SCAL_MULT
+
+} // namespace detail
+} // namespace glm

test/gtx/CMakeLists.txt

@@ -40,6 +40,7 @@ glmCreateTestGTC(gtx_quaternion)
 glmCreateTestGTC(gtx_dual_quaternion)
 glmCreateTestGTC(gtx_rotate_normalized_axis)
 glmCreateTestGTC(gtx_rotate_vector)
+glmCreateTestGTC(gtx_scalar_multiplication)
 glmCreateTestGTC(gtx_scalar_relational)
 glmCreateTestGTC(gtx_simd_vec4)
 glmCreateTestGTC(gtx_simd_mat4)

test/gtx/gtx_scalar_multiplication.cpp

@@ -0,0 +1,32 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// OpenGL Mathematics Copyright (c) 2005 - 2014 G-Truc Creation (www.g-truc.net)
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Created : 2014-09-22
+// Updated : 2014-09-22
+// Licence : This source is under MIT licence
+// File    : test/gtx/gtx_scalar_multiplication.cpp
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include <glm/glm.hpp>
+#include <glm/gtx/scalar_multiplication.hpp>
+
+int main()
+{
+	int Error(0);
+	glm::vec3 v(0.5, 3.1, -9.1);
+
+	Error += glm::all(glm::equal(v, 1.0 * v)) ? 0 : 1;
+	Error += glm::all(glm::equal(v, 1 * v)) ? 0 : 1;
+	Error += glm::all(glm::equal(v, 1u * v)) ? 0 : 1;
+
+	glm::mat3 m(1, 2, 3, 4, 5, 6, 7, 8, 9);
+	glm::vec3 w = 0.5f * m * v;
+
+	Error += glm::all(glm::equal((m*v)/2, w)) ? 0 : 1;
+	Error += glm::all(glm::equal(m*(v/2), w)) ? 0 : 1;
+	Error += glm::all(glm::equal((m/2)*v, w)) ? 0 : 1;
+	Error += glm::all(glm::equal((0.5*m)*v, w)) ? 0 : 1;
+	Error += glm::all(glm::equal(0.5*(m*v), w)) ? 0 : 1;
+
+	return Error;
+}