Implemented texture headers

src/inc/texture.hpp

@@ -0,0 +1,110 @@
+#include <iostream>
+#include <vector>
+#include <string>
+#include <map>
+
+// Generates a std::map that maps block texture names to layer indices in a 2D
+// texture array.
+
+std::map<std::string, float> mcu_load_texture_array_map(int x_res, int y_res, int channels, std::vector<std::string> paths)
+{
+	std::map<std::string, float> out;
+
+	GLsizei layers = paths.size();
+
+	// Allocate space for the texels.
+
+	GLubyte* texels = (GLubyte*)malloc(x_res * y_res * channels * layers * sizeof(GLubyte));
+
+	if (!texels)
+	{
+		std::cout << "Could not allocate enough memory for a texture array." << std::endl;
+
+		exit(9);
+	}
+
+	// Load the textures.
+
+	for (int i = 0; i < layers; i++)
+	{
+		// Load the sub-texture.
+
+		std::string path = "../tex/" + paths[i] + ".png";
+
+		int sub_x_res;
+		int sub_y_res;
+
+		int sub_channels;
+
+		unsigned char* sub_data = stbi_load(path.c_str(), &sub_x_res, &sub_y_res, &sub_channels, STBI_rgb_alpha);
+
+		if (!sub_data)
+		{
+			std::cout << "Could not load \"" << path << "\" using stbi_load." << std::endl;
+
+			exit(10);
+		}
+
+		if (sub_x_res != x_res || sub_y_res != y_res)
+		{
+			std::cout << "Dimensions of \"" << path << "\" (" << sub_x_res << ", " << sub_y_res << ") do not match the expected dimensions (" << x_res << ", " << y_res << ")." << std::endl;
+		
+			exit(11);
+		}
+
+		if (sub_channels != channels)
+		{
+			std::cout << "Channel count of \"" << path << "\" (" << sub_channels << ") does not match the expected channel count (" << channels << ")." << std::endl;
+
+			exit(12); 
+		}
+
+		// Copy the sub-texture texels to the texel array.
+
+		memcpy(texels + (i * x_res * y_res * channels), sub_data, x_res * y_res * channels);
+
+		// Free the sub-texture.
+
+		stbi_image_free(sub_data);
+
+		// Add to map.
+
+		out.emplace(paths[i], float(i));
+	}
+
+	// Generate the texture array.
+
+	GLuint texture_array = 0;
+
+	glGenTextures(1, &texture_array);
+
+	glBindTexture(GL_TEXTURE_2D_ARRAY, texture_array);
+
+	// Allocate storage for the 2D texture array.
+
+	glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, x_res, y_res, layers, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+
+	// Upload the texel data.
+
+	glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, x_res, y_res, layers, GL_RGBA, GL_UNSIGNED_BYTE, texels);
+
+	// Set up texture parameters.
+
+	glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+	glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+	// Unbind the texture array.
+
+	glBindTexture(GL_TEXTURE_2D_ARRAY, 0);
+
+	// Free the texels.
+
+	free(texels);
+
+	// Return the output std::map.
+
+	return out;
+}