minimize opengl transformation matrix by doing eye-location in software

1 files changed, 18 insertions, 9 deletions

diff --git a/src/render/dust.cc b/src/render/dust.cc
index 05266e8..a3eac6d 100644
--- a/src/render/dust.cc
+++ b/src/render/dust.cc
@@ -4,6 +4,7 @@
    the terms of the GNU General Public License version 2
 */
 
+#include "render/camera.h"
 #include "render/dust.h"
 #include "render/gl.h"
 #include "core/cvar.h"
@@ -54,6 +55,9 @@ void Dust::reset()
 
 void Dust::draw()
 {
+	float alpha = 0.0f;
+	float traillength = 0.0f;
+
 	if (!r_dust->value()) {
 		if (dust) {
 			delete dust;
@@ -95,14 +99,19 @@ void Dust::draw()
 		}
 	}
 
-	if (!core::localcontrol()->speed()) 
+	if (! core::localcontrol()->speed())
 		return;
 
-	math::Color color;
-	if (core::localcontrol()->speed() < LOWSPEEDLIMIT) {
-		color.a = core::localcontrol()->speed() / LOWSPEEDLIMIT;
-	}
-	color.a	*= DUSTMAXALPHA;
+	math::Color color(1.0f, 1.0f);
+	alpha = core::localcontrol()->speed() / LOWSPEEDLIMIT;
+	if (alpha > DUSTMAXALPHA)
+		alpha = DUSTMAXALPHA;
+	color.a	= alpha;
+
+	traillength = core::localcontrol()->speed() / LOWSPEEDLIMIT;
+	if (traillength > 1)
+		traillength = 1.0f;
+	traillength *= TRAILLENGHT;
 
 	gl::color(color);
 	gl::begin(gl::Lines);
@@ -120,11 +129,11 @@ void Dust::draw()
 			dust[i*3+2] = core::localcontrol()->location().z + (math::randomf(2) - 1) * (DUSTDISTANCE + core::localcontrol()->radius());
 		}
 
-		glVertex3fv(dust+3*i);
-
 		for (size_t j = 0; j < 3; j++)
 			v[j] = dust[i*3+j];
-		v -= core::localcontrol()->state()->axis().forward() * color.a * TRAILLENGHT;
+		v -= Camera::eye();
+		gl::vertex(v);
+		v -= core::localcontrol()->state()->axis().forward() * traillength;
 		gl::vertex(v);
 	}