[nostalgia/glutils] Add FrameBuffer type

src/nostalgia/glutils/glutils.cpp

@@ -17,6 +17,14 @@ void deleteBuffer(GLuint b) noexcept {
 	glDeleteBuffers(1, &b);
 }
 
+void deleteFrameBuffer(GLuint b) noexcept {
+	glDeleteFramebuffers(1, &b);
+}
+
+void deleteRenderBuffer(GLuint b) noexcept {
+	glDeleteRenderbuffers(1, &b);
+}
+
 void deleteTexture(GLuint t) noexcept {
 	glDeleteTextures(1, &t);
 }
@@ -26,6 +34,8 @@ void deleteVertexArray(GLuint v) noexcept {
 }
 
 template struct GLObject<deleteBuffer>;
+template struct GLObject<deleteFrameBuffer>;
+template struct GLObject<deleteRenderBuffer>;
 template struct GLObject<deleteTexture, TextureBase>;
 template struct GLObject<deleteVertexArray>;
 template struct GLObject<glDeleteProgram>;
@@ -44,10 +54,9 @@ static ox::Result<GLShader> buildShader(GLuint shaderType, const GLchar *src, co
 		oxErrorf("shader compile error in {}: {}", shaderName, errMsg);
 		return OxError(1, "shader compile error");
 	}
-	return ox::move(shader);
+	return shader;
 }
 
-[[nodiscard]]
 ox::Result<GLProgram> buildShaderProgram(const GLchar *vert, const GLchar *frag) noexcept {
 	oxRequire(vs, buildShader(GL_VERTEX_SHADER, vert, "vshad"));
 	oxRequire(fs, buildShader(GL_FRAGMENT_SHADER, frag, "fshad"));
@@ -55,7 +64,30 @@ ox::Result<GLProgram> buildShaderProgram(const GLchar *vert, const GLchar *frag)
 	glAttachShader(prgm, vs);
 	glAttachShader(prgm, fs);
 	glLinkProgram(prgm);
-	return ox::move(prgm);
+	return prgm;
+}
+
+FrameBuffer generateFrameBuffer(int width, int height) noexcept {
+	FrameBuffer fb;
+	glGenFramebuffers(1, &fb.fbo.id);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb);
+	// color texture
+	glGenTextures(1, &fb.color.id);
+	glBindTexture(GL_TEXTURE_2D, fb.color);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, fb.color, 0);
+	// depth texture
+	glGenRenderbuffers(1, &fb.depth.id);
+	glBindRenderbuffer(GL_RENDERBUFFER, fb.depth);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, fb.depth, 0);
+	// verify FBO
+	oxAssert(glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE, "Frame Buffer is incomplete");
+	// restore primary FB
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	return fb;
 }
 
 }

src/nostalgia/glutils/glutils.hpp

@@ -6,11 +6,15 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#pragma once
+
 #include <ox/std/defines.hpp>
 
 #define GL_GLEXT_PROTOTYPES 1
 #ifdef OX_OS_Darwin
+#ifndef GL_SILENCE_DEPRECATION
 #define GL_SILENCE_DEPRECATION
+#endif
 #include <OpenGL/gl3.h>
 #else
 #include <GLES3/gl3.h>
@@ -63,7 +67,7 @@ struct GLObject: public Base {
 		o.id = 0;
 	}
 
-	~GLObject() {
+	~GLObject() noexcept {
 		del(id);
 	}
 
@@ -94,22 +98,51 @@ struct GLObject: public Base {
 };
 
 void deleteBuffer(GLuint b) noexcept;
+void deleteFrameBuffer(GLuint b) noexcept;
+void deleteRenderBuffer(GLuint b) noexcept;
 void deleteTexture(GLuint t) noexcept;
 void deleteVertexArray(GLuint v) noexcept;
 
 extern template struct GLObject<deleteBuffer>;
+extern template struct GLObject<deleteFrameBuffer>;
+extern template struct GLObject<deleteRenderBuffer>;
 extern template struct GLObject<deleteTexture, TextureBase>;
 extern template struct GLObject<deleteVertexArray>;
 extern template struct GLObject<glDeleteProgram>;
 extern template struct GLObject<glDeleteShader>;
 
 using GLBuffer = GLObject<deleteBuffer>;
+using GLFrameBuffer = GLObject<deleteBuffer>;
+using GLRenderBuffer = GLObject<deleteRenderBuffer>;
 using GLShader = GLObject<glDeleteShader>;
 using GLProgram = GLObject<glDeleteProgram>;
 using GLTexture = GLObject<deleteTexture, TextureBase>;
 using GLVertexArray = GLObject<deleteVertexArray>;
 
+/**
+ * FrameBuffer holds everything needed for a usable frame buffer to exist.
+ * It differs from GLFrameBuffer in that GLFrameBuffer only manages the FBO
+ * and not its dependencies.
+ */
+struct FrameBuffer {
+	GLFrameBuffer fbo;
+	GLTexture color;
+	GLRenderBuffer depth;
+
+	constexpr operator GLuint&() noexcept {
+		return fbo.id;
+	}
+
+	constexpr operator const GLuint&() const noexcept {
+		return fbo.id;
+	}
+};
+
+
 [[nodiscard]]
 ox::Result<GLProgram> buildShaderProgram(const GLchar *vert, const GLchar *frag) noexcept;
 
-}
+[[nodiscard]]
+FrameBuffer generateFrameBuffer(int width, int height) noexcept;
+
+}