[Performous-commit] Lasse Karkkainen : Fix view/projection transforms (instrument perspective)

[Lasse Kärkkäi. <tr...@us...>]

Author: Lasse Karkkainen <tro...@tr...>
Date:   Sat Mar 12 21:39:29 2011 +0100

Fix view/projection transforms (instrument perspective)

---

 game/guitargraph.cc  |    7 +------
 game/video_driver.cc |   32 +++++++++++++++++++++++++-------
 game/video_driver.hh |   10 ++++++++++
 3 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/game/guitargraph.cc b/game/guitargraph.cc
index 62518f4..7395222 100644
--- a/game/guitargraph.cc
+++ b/game/guitargraph.cc
@@ -796,12 +796,7 @@ void GuitarGraph::draw(double time) {
 	{	// Translate, rotate and scale to place
 		using namespace glmath;
 		double frac = 0.75;  // Adjustable: 1.0 means fully separated, 0.0 means fully attached
-		/*
-		glutil::PushMatrixMode pmm(GL_PROJECTION);
-		glTranslatef(frac * offsetX, 0.0f, 0.0f);
-		glutil::PushMatrixMode pmb(GL_MODELVIEW);
-		glTranslatef((1.0 - frac) * offsetX, 0.0f, 0.0f);
-		*/
+		ViewTrans view(offsetX, 0.0, frac);
 		mat4 m = translate(vec3(0.0f, dimensions.y2(), 0.0f)) * rotate(g_angle, vec3(1.0f, 0.0f, 0.0f)) * scale(dimensions.w() / 5.0f);
 		// Do some jumping for drums
 		if (m_drums) {
diff --git a/game/video_driver.cc b/game/video_driver.cc
index 5d96406..eeddf08 100644
--- a/game/video_driver.cc
+++ b/game/video_driver.cc
@@ -148,13 +148,7 @@ void Window::updateStereo(float sepFactor) {
 }
 
 void Window::updateTransforms() {
-	// Setup the projection matrix for 2D translates
 	using namespace glmath;
-	{
-		float h = virtH();
-		const float f = near_ / z0;
-		g_projection = frustum(-0.5f * f, 0.5f * f, 0.5f * h * f, -0.5f * h * f, near_, far_);
-	}
 	mat4 position = g_projection * g_modelview;
 	mat3 normal(g_modelview);
 	for (ShaderMap::iterator it = m_shaders.begin(); it != m_shaders.end(); ++it) {
@@ -169,7 +163,7 @@ void Window::updateTransforms() {
 
 void Window::render(boost::function<void (void)> drawFunc) {
 	glutil::GLErrorChecker glerror("Window::render");
-	updateTransforms();
+	ViewTrans trans;  // Default frustum
 	if (s_width < screen->w || s_height < screen->h) glClear(GL_COLOR_BUFFER_BIT);  // Black bars
 	bool stereo = config["graphic/stereo3d"].b();
 	int type = config["graphic/stereo3dtype"].i();
@@ -318,6 +312,30 @@ void Window::resize() {
 	if (s_height > 0.8f * s_width) s_height = round(0.8f * s_width);
 }
 
+ViewTrans::ViewTrans(double offsetX, double offsetY, double frac): m_old(g_projection) {
+	// Setup the projection matrix for 2D translates
+	using namespace glmath;
+	double h = virtH();
+	const double f = near_ / z0;  // z0 to nearplane conversion factor
+	// Corners of the screen at z0
+	double x1 = -0.5, x2 = 0.5;
+	double y1 = 0.5 * h, y2 = -0.5 * h;
+	// Move the perspective point by frac of offset (i.e. move the image)
+	double persX = frac * offsetX, persY = frac * offsetY;
+	x1 -= persX; x2 -= persX;
+	y1 -= persY; y2 -= persY;
+	// Perspective projection + the rest of the offset in eye (world) space
+	g_projection = frustum(f * x1, f * x2, f * y1, f * y2, near_, far_)
+	  * translate(vec3(offsetX - persX, offsetY - persY, 0.0));
+	ScreenManager::getSingletonPtr()->window().updateTransforms();
+}
+
+ViewTrans::~ViewTrans() {
+	g_projection = m_old;
+	ScreenManager::getSingletonPtr()->window().updateTransforms();
+}
+
+
 Transform::Transform(glmath::mat4 const& m): m_old(g_modelview) {
 	g_modelview = g_modelview * m;
 	ScreenManager::getSingletonPtr()->window().updateTransforms();
diff --git a/game/video_driver.hh b/game/video_driver.hh
index c493035..eafd93d 100644
--- a/game/video_driver.hh
+++ b/game/video_driver.hh
@@ -12,6 +12,7 @@ static inline float virtH() { return float(screenH()) / screenW(); }
 
 struct SDL_Surface;
 
+/// Apply a transform to current modelview stack
 class Transform {
 public:
 	Transform(glmath::mat4 const& m);
@@ -20,6 +21,15 @@ private:
 	glmath::mat4 m_old;
 };
 
+/// Apply a subviewport with different perspective projection
+class ViewTrans {
+public:
+	ViewTrans(double offsetX = 0.0, double offsetY = 0.0, double frac = 1.0);
+	~ViewTrans();
+private:
+	glmath::mat4 m_old;
+};
+
 /// Performs a GL transform for displaying background image at far distance
 glmath::mat4 farTransform();