From 6b2ad3e55ddd0770ccd763a84c18657b12750a0e Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Wed, 11 Jan 2017 00:19:36 +0200
Subject: [PATCH] cubemap renderer progress (untested)

---
 src/rend_cubemap.cc |   86 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/rend_cubemap.h  |    9 +++++-
 src/texture.cc      |   10 ++++++
 src/texture.h       |    2 ++
 4 files changed, 106 insertions(+), 1 deletion(-)
 create mode 100644 src/rend_cubemap.cc

diff --git a/src/rend_cubemap.cc b/src/rend_cubemap.cc
new file mode 100644
index 0000000..89d1b8b
--- /dev/null
+++ b/src/rend_cubemap.cc
@@ -0,0 +1,86 @@
+#include "opengl.h"
+#include "rend_cubemap.h"
+
+RendCubemap::RendCubemap()
+{
+	cubemap = 0;
+	fbo = zbuf = 0;
+	zbuf_width = zbuf_height = 0;
+
+	proj_matrix.perspective(M_PI / 2.0, 1, 0.5, 10000);
+}
+
+void RendCubemap::set_position(const Vec3 &pos)
+{
+	this->pos = pos;
+}
+
+void RendCubemap::set_cubemap(Texture *cubemap)
+{
+	this->cubemap = cubemap;
+}
+
+void RendCubemap::draw() const
+{
+	static const Vec3 targ[] = {
+		Vec3{1, 0, 0}, Vec3{-1, 0, 0},
+		Vec3{0, 1, 0}, Vec3{0, -1, 0},
+		Vec3{0, 0, 1}, Vec3{0, 0, -1}
+	};
+	static const Vec3 up[] = {
+		Vec3{0, 1, 0}, Vec3{0, 1, 0},
+		Vec3{0, 0, 1}, Vec3{0, 0, -1},
+		Vec3{0, 1, 0}, Vec3{0, 1, 0}
+	};
+	if(!cubemap) return;
+
+	glMatrixMode(GL_PROJECTION);
+	glPushMatrix();
+	glLoadMatrixf(proj_matrix[0]);
+
+	for(int i=0; i<6; i++) {
+		Mat4 vmat;
+		vmat.inv_lookat(pos, targ[i], up[i]);
+
+		glMatrixMode(GL_MODELVIEW);
+		if(i == 0) glPushMatrix();
+		glLoadMatrixf(vmat[0]);
+
+		setup(i);
+
+		Renderer::draw();
+	}
+
+	glMatrixMode(GL_PROJECTION);
+	glPopMatrix();
+	glMatrixMode(GL_MODELVIEW);
+	glPopMatrix();
+}
+
+void RendCubemap::draw_object(Object *obj) const
+{
+	obj->draw();
+}
+
+void RendCubemap::setup(int face_idx) const
+{
+	if(!cubemap) return;
+
+	if(!fbo) {
+		glGenFramebuffers(1, &fbo);
+	}
+	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+	if(!zbuf) {
+		glGenRenderbuffers(1, &zbuf);
+		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, zbuf);
+	}
+
+	if(zbuf_width != cubemap->get_width() || zbuf_height != cubemap->get_height()) {
+		zbuf_width = cubemap->get_width();
+		zbuf_height = cubemap->get_height();
+		glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, zbuf_width, zbuf_height);
+	}
+
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+			GL_TEXTURE_CUBE_MAP_POSITIVE_X + face_idx, cubemap->get_id(), 0);
+}
diff --git a/src/rend_cubemap.h b/src/rend_cubemap.h
index 00995c7..4bacd9e 100644
--- a/src/rend_cubemap.h
+++ b/src/rend_cubemap.h
@@ -8,13 +8,20 @@ class RendCubemap : public Renderer {
 private:
 	Vec3 pos;
 	Texture *cubemap;
-	unsigned int fbo, zbuf;
+	mutable unsigned int fbo, zbuf;
+	mutable int zbuf_width, zbuf_height;
+	Mat4 proj_matrix;
+
+	void setup(int face_idx) const;
 
 public:
+	RendCubemap();
+
 	void set_position(const Vec3 &pos);
 	void set_cubemap(Texture *cubemap);
 
 	void draw() const;
+	void draw_object(Object *obj) const;
 };
 
 #endif	// REND_CUBEMAP_H_
diff --git a/src/texture.cc b/src/texture.cc
index ff4d1b5..f4f7cfe 100644
--- a/src/texture.cc
+++ b/src/texture.cc
@@ -126,6 +126,16 @@ int Texture::get_size(int dim) const
 	return sz[dim];
 }
 
+int Texture::get_width() const
+{
+	return sz[0];
+}
+
+int Texture::get_height() const
+{
+	return sz[1];
+}
+
 unsigned int Texture::get_id() const
 {
 	return id;
diff --git a/src/texture.h b/src/texture.h
index 5e18e7a..5c4bf3c 100644
--- a/src/texture.h
+++ b/src/texture.h
@@ -42,6 +42,8 @@ public:
 	unsigned int get_format() const;
 
 	int get_size(int dim) const;
+	int get_width() const;
+	int get_height() const;
 
 	void create(int xsz, int ysz, TextureType type = TEX_2D, unsigned int ifmt = GL_RGBA);
 	void create_default(TextureType type = TEX_2D);
-- 
1.7.10.4