1 files changed, 83 insertions, 0 deletions
diff --git a/graphics/texture.cpp b/graphics/texture.cpp
new file mode 100644
index 0000000..5539f6d
--- /dev/null
+++ b/graphics/texture.cpp
@@ -0,0 +1,83 @@
+#include "texture.h"
+#include "lodepng.h"
+#include <vector>
+#include <cmath>
+
+void graphics::Texture::makePowerOfTwo()
+{
+	// Texture size must be power of two for the primitive OpenGL version this is written for. Find next power of two.
+	int u2 = 1; while (u2 < m_width) u2 *= 2;
+	int v2 = 1; while (v2 < m_height) v2 *= 2;
+	if (u2 == m_width && v2 == m_height)
+		return;
+
+	// Make power of two version of the image.
+	std::vector<unsigned char> image2(u2 * v2 * 4);
+	for (int i = 0; i < v2; i++)
+		for (int j = 0; j < u2; j++)
+		{
+			float x = (m_width-1) * j / (float)u2;
+			float y = (m_height-1) * i / (float)v2;
+			int x_L = (int)floorf(x);
+			int x_U = (int)ceilf(x);
+			int y_L = (int)floorf(y);
+			int y_U = (int)ceilf(y);
+			float sx = x - x_L;
+			float sy = y - y_L;
+
+			for (int c = 0; c < 4; c++)
+			{
+				float valx1 = (1.0f - sx) * m_buffer[4 * (y_L*m_width + x_L) + c] + sx * m_buffer[4 * (y_L*m_width + x_U) + c];
+				float valx2 = (1.0f - sx) * m_buffer[4 * (y_U*m_width + x_L) + c] + sx * m_buffer[4 * (y_U*m_width + x_U) + c];
+				float valy = (1.0f - sy) * valx1 + sy * valx2;
+				image2[4 * (i*u2 + j) + c] = (unsigned char)roundf(valy);
+			}
+		}
+
+	m_buffer = std::move(image2);
+	m_width = u2;
+	m_height = v2;
+}
+
+bool graphics::Texture::load(const std::string & file)
+{
+	unsigned int error = lodepng::decode(m_buffer, m_width, m_height, file.c_str());
+	return !error;
+}
+
+void graphics::Texture::buildGLTexture()
+{
+	glEnable(GL_TEXTURE_2D);
+	glGenTextures(1, &m_id);
+	glBindTexture(GL_TEXTURE_2D, m_id);
+	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST); 
+	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexImage2D(GL_TEXTURE_2D, 0, 4, m_width, m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, &m_buffer[0]);
+	glGenerateMipmap(GL_TEXTURE_2D);
+	glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+graphics::Texture::Texture(const std::string & filename)
+{
+	m_filename = filename;
+	if (!load(filename))
+		return;
+	makePowerOfTwo();
+	buildGLTexture();
+}
+
+GLuint graphics::TextureManager::getTexture(std::string file)
+{
+	auto iter = textures.find(file);
+	if (iter != textures.end())
+	{
+		return iter->second.getID();
+	}
+	else
+	{
+		textures.insert(std::make_pair(file, Texture(file)));
+	}
+	return GLuint();
+}