Ability to load texture into fbo

.gitignore

@@ -0,0 +1,3 @@
+build
+.DS_Store
+xcuserdata

J.xcodeproj/project.pbxproj

@@ -16,6 +16,7 @@
 		4268136F140A321800CBF943 /* J.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4268136E140A321800CBF943 /* J.mm */; };
 		4283A45F14115AC400036A5D /* interpolator.h in Headers */ = {isa = PBXBuildFile; fileRef = 4283A45E14115AC300036A5D /* interpolator.h */; };
 		4283A4641411707700036A5D /* array.h in Headers */ = {isa = PBXBuildFile; fileRef = 4283A4631411707700036A5D /* array.h */; };
+		429E3BAB159616FD0044306C /* texture_objc.mm in Sources */ = {isa = PBXBuildFile; fileRef = 429E3BAA159616FD0044306C /* texture_objc.mm */; };
 		42ED6A6B140A380000402F76 /* fbo.h in Headers */ = {isa = PBXBuildFile; fileRef = 42ED6A68140A380000402F76 /* fbo.h */; };
 		42ED6A6C140A380000402F76 /* shader.h in Headers */ = {isa = PBXBuildFile; fileRef = 42ED6A69140A380000402F76 /* shader.h */; };
 		42ED6A6D140A380000402F76 /* to_string.h in Headers */ = {isa = PBXBuildFile; fileRef = 42ED6A6A140A380000402F76 /* to_string.h */; };
@@ -33,6 +34,9 @@
 		4268136E140A321800CBF943 /* J.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = J.mm; sourceTree = "<group>"; };
 		4283A45E14115AC300036A5D /* interpolator.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = interpolator.h; sourceTree = "<group>"; };
 		4283A4631411707700036A5D /* array.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = array.h; sourceTree = "<group>"; };
+		429E3BA715960FCA0044306C /* texture.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = texture.h; sourceTree = "<group>"; };
+		429E3BA9159616C00044306C /* texture_objc.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = texture_objc.h; sourceTree = "<group>"; };
+		429E3BAA159616FD0044306C /* texture_objc.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = texture_objc.mm; sourceTree = "<group>"; };
 		42ED6A68140A380000402F76 /* fbo.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = fbo.h; sourceTree = "<group>"; };
 		42ED6A69140A380000402F76 /* shader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = shader.h; sourceTree = "<group>"; };
 		42ED6A6A140A380000402F76 /* to_string.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = to_string.h; sourceTree = "<group>"; };
@@ -115,6 +119,9 @@
 				425E9DF1140A74DA00A81A65 /* basic.h */,
 				425E9DF5140A774D00A81A65 /* basic.cpp */,
 				42ED6A68140A380000402F76 /* fbo.h */,
+				429E3BA715960FCA0044306C /* texture.h */,
+				429E3BA9159616C00044306C /* texture_objc.h */,
+				429E3BAA159616FD0044306C /* texture_objc.mm */,
 				425E9DF8140A7EB400A81A65 /* fbo.mm */,
 				42ED6A69140A380000402F76 /* shader.h */,
 			);

J/fbo.h

@@ -23,6 +23,7 @@
 #include "to_string.h"
 
 #include "basic.h"
+#include "texture.h"
 
 @class EAGLContext;
 @class CAEAGLLayer;
@@ -45,14 +46,15 @@ public:
 
 public:
     // standard ctor, makes use of textures
-	fbo(int width, int height) : width(width), height(height), fbo_number(0), renderbuffers(), texture_id(0) {
+	template <typename Texture = no_texture>
+	fbo(int width, int height, Texture const & texture = no_texture()) : width(width), height(height), fbo_number(0), renderbuffers(), texture_id(0) {
 		glGenFramebuffers(1, &fbo_number);
 		bind();
 
 		// generate texture
 		glGenTextures(1, &texture_id);
 		glBindTexture(GL_TEXTURE_2D, texture_id);
-		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+		bool should_clear = !make_tex(texture);
 		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_id, 0);
 
 		// attach depth
@@ -61,8 +63,10 @@ public:
 		check_error();
 		check_status();
 
-		glClearColor(0.0, 0.0, 0.0, 0.0);
-		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+		if(should_clear){
+			glClearColor(0.0, 0.0, 0.0, 0.0);
+			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+		}
 
 		unbind();
 	}
@@ -96,6 +100,17 @@ public:
 	}
 
 private:
+	template <typename Texture>
+	bool make_tex(Texture const & texture){
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, Texture::gl_format, Texture::gl_type, texture.data());
+		return true;
+	}
+	
+	bool make_tex(no_texture const &){
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
+		return false;
+	}
+	
 	void bind(){
 		glBindFramebuffer(GL_FRAMEBUFFER, fbo_number);
 		check_error();

J/texture.h

@@ -0,0 +1,86 @@
+//
+//  texture.h
+//  J
+//
+//  Created by Joshua Moerman on 6/23/12.
+//  Copyright (c) 2012 Vadovas. All rights reserved.
+//
+
+#ifndef J_texture_h
+#define J_texture_h
+
+#include "basic.h"
+#include <vector>
+#include <algorithm>
+
+namespace J {
+
+struct no_texture {};
+	
+template <typename T>
+struct gl_type {};
+
+template <>
+struct gl_type<uint8_t> {
+	static constexpr GLenum value = GL_UNSIGNED_BYTE;
+};
+
+template <typename T = uint8_t>
+struct rgba {
+	typedef typename std::vector<T>::iterator iterator;
+	typedef typename std::vector<T>::iterator const_iterator;
+	typedef typename std::vector<T>::size_type size_type;
+	static constexpr GLenum gl_type = J::gl_type<T>::value;
+	static constexpr GLenum gl_format = GL_RGBA;
+	
+	rgba(size_type w, size_type h, T const * data = nullptr)
+	: width_(w)
+	, height_(h)
+	, pixels(w*h*4){
+		if(data)
+			std::copy_n(data, w*h*4, pixels.begin());
+	}
+	
+	size_type size() const { return pixels.size(); }
+	size_type width() const { return width; }
+	size_type height() const { return height; }
+	
+	struct row_proxy {
+		row_proxy(T* data) : data(data) {}
+		T& operator[](size_type x){ return data[x]; }
+		T operator[](size_type x) const { return data[x]; }
+		T* data;
+	};
+	
+	row_proxy operator[](size_type y){
+		return &pixels[y*width()];
+	}
+	
+	struct const_row_proxy {
+		const_row_proxy(T const * data) : data(data) {}
+		T operator[](size_type x) const { return data[x]; }
+		T const * data;
+	};
+	
+	const_row_proxy operator[](size_type y) const {
+		return &pixels[y*width()];
+	}
+	
+	T * data() { return pixels.data(); }
+	T const * data() const { return pixels.data(); }
+	
+	iterator begin() { return pixels.begin(); }
+	iterator end() { return pixels.begin(); }
+	
+	const_iterator begin() const { return pixels.begin(); }
+	const_iterator end() const { return pixels.begin(); }
+	
+private:
+	size_type width_;
+	size_type height_;
+	std::vector<T> pixels;
+};
+	
+}
+
+#endif

J/texture_objc.h

@@ -0,0 +1,22 @@
+//
+//  texture_objc.h
+//  J
+//
+//  Created by Joshua Moerman on 6/23/12.
+//  Copyright (c) 2012 Vadovas. All rights reserved.
+//
+
+#ifndef J_texture_objc_h
+#define J_texture_objc_h
+
+#include "texture.h"
+
+@class UIImage;
+
+namespace J {
+
+rgba<> texture_from_UIImage(UIImage * image);
+
+}
+
+#endif

J/texture_objc.mm

@@ -0,0 +1,23 @@
+//
+//  texture_objc.mm
+//  J
+//
+//  Created by Joshua Moerman on 6/23/12.
+//  Copyright (c) 2012 Vadovas. All rights reserved.
+//
+
+#include "texture_objc.h"
+
+#import <UIKit/UIKit.h>
+//#import <Quartz/Quartz.h>
+
+namespace J {
+	rgba<> texture_from_UIImage(UIImage * image){
+		CGImageRef cgImage = image.CGImage;
+		CGDataProviderRef provider = CGImageGetDataProvider(cgImage);
+		CFDataRef bitmapData = CGDataProviderCopyData(provider);
+		CFDataGetBytePtr(bitmapData);
+		
+		return rgba<>(image.size.width, image.size.height, CFDataGetBytePtr(bitmapData));
+	}
+}