Added billboarding

pokepetter · Jul 26, 2024 · d7e7759 · d7e7759
1 parent 162808e
commit d7e7759
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Showing 2 changed files with 36 additions and 5 deletions.
diff --git a/samples/particle_engine/explosion.py b/samples/particle_engine/explosion.py
@@ -40,10 +40,11 @@ def generate_particles(n):
     particles=generate_particles(100),
     gravity=Vec3(0, 1, 0),
     position=Vec3(0, 0, 0),
-    model="cube",
+    model="quad",
     texture="explosion_sprite_sheet",
     frames=Vec2(8,1),
     frames_per_loop=8,
+    billboard=True,
 )
 
 

diff --git a/ursina/prefabs/particle_manager.py b/ursina/prefabs/particle_manager.py
@@ -289,8 +289,8 @@ class ParticleManager(Entity):
         vertex="""
                 #version 430
 
-                uniform mat4 p3d_ModelViewProjectionMatrix;
                 uniform mat4 p3d_ModelViewMatrix;
+                uniform mat4 p3d_ProjectionMatrix;
                 in vec4 p3d_Vertex;
                 in vec2 p3d_MultiTexCoord0;
 
@@ -306,6 +306,7 @@ class ParticleManager(Entity):
                 uniform float elapsed_time;
                 uniform vec3 gravity;
                 uniform bool looping;
+                uniform bool billboard;
 
                 flat out int discard_frag;
                 out vec2 texcoord;
@@ -343,8 +344,24 @@ class ParticleManager(Entity):
                     vec3 adjusted_position = (position+velocity*adjusted_time + 0.5*gravity*adjusted_time*adjusted_time);
 
                     progress = life;
-
-                    gl_Position = p3d_ModelViewProjectionMatrix * vec4(v + adjusted_position, p3d_Vertex.w);
+                    
+                    
+                    if (billboard) {
+                        mat4 custom_ModelViewMatrix = p3d_ModelViewMatrix;
+                        custom_ModelViewMatrix[0][0] = 1;
+                        custom_ModelViewMatrix[0][1] = 0;
+                        custom_ModelViewMatrix[0][2] = 0;
+                        custom_ModelViewMatrix[1][0] = 0;
+                        custom_ModelViewMatrix[1][1] = 1;
+                        custom_ModelViewMatrix[1][2] = 0;
+                        custom_ModelViewMatrix[2][0] = 0;
+                        custom_ModelViewMatrix[2][1] = 0;
+                        custom_ModelViewMatrix[2][2] = 1;
+                        vec4 temp = custom_ModelViewMatrix * vec4((v + adjusted_position), p3d_Vertex.w);
+                        gl_Position = p3d_ProjectionMatrix * temp;
+                    } else {
+                        gl_Position = p3d_ProjectionMatrix * p3d_ModelViewMatrix * vec4((v + adjusted_position), p3d_Vertex.w);
+                    }
                 }""",
         fragment="""
                     #version 430
@@ -364,7 +381,7 @@ class ParticleManager(Entity):
                         int frame = int(progress * frames_per_loop);
                         int x = frame % int(frames.x);
                         int y = int(mod(frame / int(frames.x), int(frames.y)));
-                        vec2 adjusted_texcoord = vec2(texcoord.x / frames.x + x / frames.x, texcoord.y / frames.y + y / frames.y);
+                        vec2 adjusted_texcoord = vec2((texcoord.x + x) / frames.x, (texcoord.y + y) / frames.y);
                         fragColor = texture(p3d_Texture0, adjusted_texcoord)  * p3d_ColorScale * new_color;
                     }""")
 
@@ -380,6 +397,7 @@ def __init__(
         trail_resolution=10,
         frames=None,
         frames_per_loop=None,
+        billboard=False,
         **kwargs,
     ):
         """Creates a new ParticleManager
@@ -403,6 +421,7 @@ def __init__(
         self.simulation_speed = simulation_speed
         self.gravity = gravity
         self.trail_segments = trail_segments
+        self.billboard = billboard
         self._particles = particles
 
         self.frames = frames if frames is not None else Vec2(1, 1)
@@ -616,6 +635,17 @@ def frames_per_loop(self, value):
         self._frames_per_loop = value
         self.set_shader_input("frames_per_loop", value)
 
+
+
+    @property
+    def billboard(self):
+        return self._billboard
+
+    @billboard.setter
+    def billboard(self, value):
+        self._billboard = value
+        self.set_shader_input("billboard", value)
+
     def __setattr__(self, key, value):
         if key.startswith("trail_"):
             setattr(self.trail, key[6:], value)