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_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;