From 540e0d6db808111ed1232e1c518273ab77a94340 Mon Sep 17 00:00:00 2001
From: Martin Felis <martin@fysx.org>
Date: Fri, 16 Feb 2018 22:06:09 +0100
Subject: [PATCH] Implemente LookAt and using values from camera for near and
 far values for depth rendering

---
 src/SimpleMath/SimpleMathGL.h | 16 +++++++++++++++
 src/modules/RenderModule.cc   | 37 +++++++++++++++++++++++------------
 src/modules/RenderModule.h    | 18 ++++++++---------
 3 files changed, 50 insertions(+), 21 deletions(-)

diff --git a/src/SimpleMath/SimpleMathGL.h b/src/SimpleMath/SimpleMathGL.h
index 5de0fde..6541852 100644
--- a/src/SimpleMath/SimpleMathGL.h
+++ b/src/SimpleMath/SimpleMathGL.h
@@ -101,6 +101,22 @@ inline Matrix44f Perspective(float fovy, float aspect,
 			);
 }
 
+inline Matrix44f LookAt(
+		const Vector3f& eye,
+		const Vector3f& poi,
+		const Vector3f& up) {
+	Vector3f d = (poi - eye).normalized();
+	Vector3f s = d.cross(up.normalized());
+	Vector3f u = s.cross(d);
+
+	return Matrix44f(
+			s[0], u[0], -d[0], 0.0f,
+			s[1], u[1], -d[1], 0.0f,
+			s[2], u[2], -d[2], 0.0f,
+			-eye[0], -eye[1], -eye[2], 1.0f
+			);
+}
+
 /** Quaternion 
  *
  * order: x,y,z,w
diff --git a/src/modules/RenderModule.cc b/src/modules/RenderModule.cc
index 9ceb30c..33d670b 100644
--- a/src/modules/RenderModule.cc
+++ b/src/modules/RenderModule.cc
@@ -8,9 +8,9 @@ using namespace SimpleMath::GL;
 struct Renderer;
 
 static const GLfloat g_vertex_buffer_data[] = {
-	-0.9f, -0.9f, 1.0f,
-	0.9f, -0.9f, -1.0f,
-	0.0f, 0.9f, 0.0f
+	-0.7f, -0.9f, 0.0f,
+	0.9f, -0.9f, 0.0f,
+	0.0f, 0.9f, 1.0f
 };
 
 static const GLfloat g_quad_vertex_buffer_data[] = {
@@ -117,7 +117,12 @@ const struct module_api MODULE_API = {
 //
 // Camera
 //
-void Camera::updateMatrices() {
+void Camera::UpdateMatrices() {
+	mViewMatrix = LookAt(eye, poi, up);
+
+	if (orthographic) {
+		mProjectionMatrix = Ortho(-1.0f, 1.0f, -1.0f, 1.0f, near, far);
+	}
 }
 
 
@@ -178,9 +183,20 @@ void Renderer::RenderGl() {
 	if (width != mWidth || height != mHeight)
 		Resize(width, height);
 
-	mCamera.mtxProj = Ortho(-1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f);
+	mCamera.eye = Vector3f (0.0f, 0.0f, 1.0f);
+	mCamera.poi = Vector3f (0.0f, 0.0f, 0.0f);
+	mCamera.up = Vector3f (0.0f, 1.0f, 0.0f);
+	mCamera.near = 0.0f;
+	mCamera.far = 1.0f;
+	mCamera.orthographic = true;
 
-	Matrix44f model_view_projection = mCamera.mtxProj * mCamera.mtxView;
+	mCamera.UpdateMatrices();
+
+	Matrix44f model_matrix = TranslateMat44(0.0f, 0.0f, 0.0f);
+	Matrix44f model_view_projection = 
+		model_matrix
+		* mCamera.mViewMatrix
+		* mCamera.mProjectionMatrix;
 
 	// enable the render target
 	glBindFramebuffer(GL_FRAMEBUFFER, mRenderTarget.mFrameBufferId);
@@ -198,7 +214,6 @@ void Renderer::RenderGl() {
 	glUseProgram(mDefaultProgram.mProgramId);
 	glUniformMatrix4fv(muDefaultModelViewProjection, 1, GL_FALSE, model_view_projection.data());
 	glUniform4fv(muDefaultColor, 1, Vector4f(1.0f, 0.0f, 0.0f, 1.0f).data());
-	glUniformMatrix4fv(muDefaultModelViewProjection, 1, GL_FALSE, model_view_projection.data());
 
 	glEnableVertexAttribArray(0);
 	glBindBuffer(GL_ARRAY_BUFFER, mMesh.mVertexBuffer);
@@ -223,9 +238,7 @@ void Renderer::RenderGui() {
 
 	bool render_color = false;
 
-	mCamera.mtxProj = Ortho(-1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f);
-
-	Matrix44f model_view_projection = mCamera.mtxProj * mCamera.mtxView;
+	Matrix44f model_view_projection = Matrix44f::Identity();
 
 	if (render_color) {
 		// Render the full screen quad
@@ -240,8 +253,8 @@ void Renderer::RenderGui() {
 		glBindTexture(GL_TEXTURE_2D, mRenderTarget.mDepthTexture);
 		glUniformMatrix4fv(muRenderQuadModelViewProj, 1, GL_FALSE, model_view_projection.data());
 		glUniform1i(muRenderQuadTexture, 0);
-		glUniform1f(muRenderQuadDepthNear, -1.0);
-		glUniform1f(muRenderQuadDepthFar, 1.0);
+		glUniform1f(muRenderQuadDepthNear, mCamera.near);
+		glUniform1f(muRenderQuadDepthFar, mCamera.far);
 	}
 
 	glEnableVertexAttribArray(0);
diff --git a/src/modules/RenderModule.h b/src/modules/RenderModule.h
index aabe80b..4135b96 100644
--- a/src/modules/RenderModule.h
+++ b/src/modules/RenderModule.h
@@ -24,8 +24,8 @@ struct Camera {
 	float width;
 	float height;
 
-	Matrix44f mtxProj;
-	Matrix44f mtxView;
+	Matrix44f mProjectionMatrix;
+	Matrix44f mViewMatrix;
 
 	Camera() :
 		eye {5.f, 4.f, 5.f},
@@ -38,27 +38,27 @@ struct Camera {
 		width (-1.f),
 		height (-1.f),
 
-		mtxProj (
+		mProjectionMatrix (
 			1.f, 0.f, 0.f, 0.f,
 			0.f, 1.f, 0.f, 0.f,
 			0.f, 0.f, 1.f, 0.f,
 			0.f, 0.f, 0.f, 1.f),
-		mtxView (
+		mViewMatrix (
 			1.f, 0.f, 0.f, 0.f,
 			0.f, 1.f, 0.f, 0.f,
 			0.f, 0.f, 1.f, 0.f,
 			0.f, 0.f, 0.f, 1.f)
 		{}
 
-	void updateMatrices();
+	void UpdateMatrices();
 };
 
 struct Light {
 	Vector3f pos;
 	Vector3f dir;
 
-	float mtxView[16];
-	float mtxProj[16];
+	float mViewMatrix[16];
+	float mProjectionMatrix[16];
 	float mtxLight[16];
 	float mtxShadow[16];
 
@@ -73,13 +73,13 @@ struct Light {
 	Light() :
 		pos (Vector3f(0.f, 10.f, 10.f)),
 		dir (Vector3f(-1.f, -1.f, -1.f)),
-		mtxView {
+		mViewMatrix {
 			1.f, 0.f, 0.f, 0.f,
 			0.f, 1.f, 0.f, 0.f,
 			0.f, 0.f, 1.f, 0.f,
 			0.f, 0.f, 0.f, 1.f
 		},
-		mtxProj {
+		mProjectionMatrix {
 			1.f, 0.f, 0.f, 0.f,
 			0.f, 1.f, 0.f, 0.f,
 			0.f, 0.f, 1.f, 0.f,