refactor: transparent render (#14)

* fix(renderer): defer uniform location retrieval and add view matrix in outline rendering

* refactor(gameplay): encapsulate per-type vertex data into VertexData struct

* feat(rendering): separate transparent blocks into discard and blend modes

* feat(renderer): implement order-independent transparency

* fix(shaders): reduce alpha discard threshold to 0.8

assets/shaders/block_accumulation_f_shader.glsl

@@ -0,0 +1,28 @@
+#version 460
+
+layout (location = 0) out vec4 accum;
+layout (location = 1) out float reveal;
+
+in vec2 tc;
+flat in int tex_layer;
+in float v_depth;
+layout (binding = 0) uniform sampler2DArray samp;
+
+float weight(float z, float a) {
+    float intermediate = 0.03 / (1e-5 + pow(z / 200.0, 4.0));
+    
+    return a * clamp(intermediate, 1e-2, 3e2);
+}
+
+void main() {
+    vec4 color = texture(samp, vec3(tc, tex_layer));
+    float alpha = color.a;
+    if (alpha < 1e-4) discard;
+
+
+    float w = weight(v_depth, alpha);
+
+    accum = vec4(color.rgb * alpha * w, alpha * w);
+
+    reveal = alpha;
+}

assets/shaders/block_accumulation_v_shader.glsl

@@ -0,0 +1,21 @@
+#version 460
+
+layout (location = 0) in vec3 pos;
+layout (location = 1) in vec2 texCoord;
+layout (location = 2) in float layer;
+out vec2 tc;
+flat out int tex_layer;
+out float v_depth;
+
+uniform mat4 mv_matrix;
+uniform mat4 proj_matrix;
+
+
+
+void main(void) {
+    vec4 view_pos = mv_matrix * vec4(pos, 1.0);
+    gl_Position = proj_matrix * view_pos;
+    tc = texCoord;
+    tex_layer = int(layer);
+    v_depth = -view_pos.z;
+}

assets/shaders/block_composite_f_shader.glsl

@@ -0,0 +1,19 @@
+#version 460
+
+uniform sampler2D u_accumTex;
+uniform sampler2D u_revealTex;
+in vec2 TexCoord;
+out vec4 FragColor;
+
+void main() {
+    vec4 a = texture(u_accumTex, TexCoord);
+    float r = texture(u_revealTex, TexCoord).r;
+
+    if (a.a < 1e-4) discard;
+
+    vec3 color = a.rgb / max(a.a, 1e-5);
+    float transmittance = r;
+    float opacity = 1.0 - transmittance;
+
+    FragColor = vec4(color * opacity, opacity);
+}

assets/shaders/block_composite_v_shader.glsl

@@ -0,0 +1,11 @@
+#version 460
+
+layout (location = 0) in vec2 pos;
+layout (location = 1) in vec2 texCoord;
+
+out vec2 TexCoord;
+
+void main() {
+    gl_Position = vec4(pos.x, pos.y, 0.0, 1.0);
+    TexCoord = texCoord;
+}

assets/shaders/block_f_shader.glsl

@@ -8,7 +8,7 @@ layout (binding = 0) uniform sampler2DArray samp;
 
 void main(void) {
     color = texture(samp, vec3(tc, tex_layer));
-    if (color.a < 0.1) {
+    if (color.a < 0.8) {
         discard;
     }
     //color = varyingColor;