premult alpha for sprites and bitmap fonts, bm font outline support, optional vertex snapping

samples/bin/library/arial_bm.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:2f1044cd99d8bd2b0576b06928493cf7cdad421bae5d71c56a436cc33f59c30a
-size 217444
+oid sha256:cdd1e2d175c5109ec5840ea37093e7f745fbf618b709ee334b7459ef1567960a
+size 61729

samples/bin/library/font_bm_material.json

@@ -3,7 +3,7 @@
         "shader" : "font_bm_shader.json",
         "state_block" : {
             "blending_state" : {
-                "src_factor" : "src_alpha",
+                "src_factor" : "one",
                 "dst_factor" : "one_minus_src_alpha"
             },
             "capabilities_state" : {

samples/bin/library/font_bm_shader.frag

@@ -1,8 +1,26 @@
 uniform sampler2D u_texture;
 
+uniform float u_glyph_dilate;
+uniform float u_outline_width;
+uniform vec4 u_outline_color;
+
 varying vec2 v_st0;
-varying vec4 v_color;
+varying vec4 v_color0;
 
 void main() {
-    gl_FragColor = texture2D(u_texture, v_st0) * v_color;
+    vec4 t = texture2D(u_texture, v_st0);
+
+    float glyph_alpha = t.a;
+    float outline_alpha = t.r;
+
+    vec4 glyph_color = vec4(v_color0.rgb * v_color0.a, v_color0.a);
+    vec4 outline_color = vec4(u_outline_color.rgb * u_outline_color.a, u_outline_color.a);
+
+    vec2 layers_mask = vec2(
+        step(0.0001, v_color0.a),
+        step(0.0001, u_outline_color.a * u_outline_width));
+
+    gl_FragColor =
+        layers_mask.x * glyph_alpha * glyph_color +
+        layers_mask.y * outline_alpha * outline_color * (1.0 - glyph_alpha);
 }

samples/bin/library/font_bm_shader.vert

@@ -1,3 +1,4 @@
+uniform vec2 u_screen_s;
 uniform mat4 u_matrix_m;
 uniform mat4 u_matrix_vp;
 
@@ -6,10 +7,33 @@ attribute vec2 a_st0;
 attribute vec4 a_color0;
 
 varying vec2 v_st0;
-varying vec4 v_color;
+varying vec4 v_color0;
+
+#define VERTEX_SNAPPING_ON
+
+vec2 round(vec2 v) {
+    return vec2(
+        floor(v.x + 0.5),
+        floor(v.y + 0.5));
+}
+
+vec4 pixel_snap(vec4 pos) {
+    vec2 hpc = u_screen_s * 0.5;
+    vec2 pixel_pos = round((pos.xy / pos.w) * hpc);
+    pos.xy = pixel_pos / hpc * pos.w;
+    return pos;
+}
+
+vec4 vertex_to_homo(vec3 pos) {
+    return vec4(pos, 1.0) * u_matrix_m * u_matrix_vp;
+}
 
 void main() {
     v_st0 = vec2(a_st0.s, 1.0 - a_st0.t);
-    v_color = a_color0;
-    gl_Position = vec4(a_vertex, 1.0) * u_matrix_m * u_matrix_vp;
+    v_color0 = a_color0;
+#ifndef VERTEX_SNAPPING_ON
+    gl_Position = vertex_to_homo(a_vertex);
+#else
+    gl_Position = pixel_snap(vertex_to_homo(a_vertex));
+#endif
 }

samples/bin/library/font_sdf_shader.frag

@@ -1,3 +1,7 @@
+#ifdef GL_OES_standard_derivatives
+#  extension GL_OES_standard_derivatives : require
+#endif
+
 uniform sampler2D u_texture;
 
 uniform float u_glyph_dilate;
@@ -5,7 +9,7 @@ uniform float u_outline_width;
 uniform vec4 u_outline_color;
 
 varying vec2 v_st0;
-varying vec4 v_color;
+varying vec4 v_color0;
 
 void main() {
     float distance = texture2D(u_texture, v_st0).a;
@@ -17,13 +21,14 @@ void main() {
     float glyph_alpha = smoothstep(glyph_center - width, glyph_center + width, distance);
     float outline_alpha = smoothstep(outline_center - width, outline_center + width, distance);
 
-    vec4 glyph_color = vec4(v_color.rgb * v_color.a, v_color.a);
+    vec4 glyph_color = vec4(v_color0.rgb * v_color0.a, v_color0.a);
     vec4 outline_color = vec4(u_outline_color.rgb * u_outline_color.a, u_outline_color.a);
 
     vec2 layers_mask = vec2(
-        step(0.01, v_color.a),
-        step(0.01, u_outline_color.a * u_outline_width));
+        step(0.0001, v_color0.a),
+        step(0.0001, u_outline_color.a * u_outline_width));
 
-    gl_FragColor = glyph_alpha * glyph_color * layers_mask.x +
-        outline_alpha * outline_color * layers_mask.y * (1.0 - glyph_alpha);
+    gl_FragColor =
+        layers_mask.x * glyph_alpha * glyph_color +
+        layers_mask.y * outline_alpha * outline_color * (1.0 - glyph_alpha);
 }

samples/bin/library/font_sdf_shader.vert

@@ -1,3 +1,4 @@
+uniform vec2 u_screen_s;
 uniform mat4 u_matrix_m;
 uniform mat4 u_matrix_vp;
 
@@ -6,10 +7,33 @@ attribute vec2 a_st0;
 attribute vec4 a_color0;
 
 varying vec2 v_st0;
-varying vec4 v_color;
+varying vec4 v_color0;
+
+#define VERTEX_SNAPPING_ON
+
+vec2 round(vec2 v) {
+    return vec2(
+        floor(v.x + 0.5),
+        floor(v.y + 0.5));
+}
+
+vec4 pixel_snap(vec4 pos) {
+    vec2 hpc = u_screen_s * 0.5;
+    vec2 pixel_pos = round((pos.xy / pos.w) * hpc);
+    pos.xy = pixel_pos / hpc * pos.w;
+    return pos;
+}
+
+vec4 vertex_to_homo(vec3 pos) {
+    return vec4(pos, 1.0) * u_matrix_m * u_matrix_vp;
+}
 
 void main() {
     v_st0 = vec2(a_st0.s, 1.0 - a_st0.t);
-    v_color = a_color0;
-    gl_Position = vec4(a_vertex, 1.0) * u_matrix_m * u_matrix_vp;
+    v_color0 = a_color0;
+#ifndef VERTEX_SNAPPING_ON
+    gl_Position = vertex_to_homo(a_vertex);
+#else
+    gl_Position = pixel_snap(vertex_to_homo(a_vertex));
+#endif
 }

samples/bin/library/model_shader.frag

@@ -3,6 +3,5 @@ uniform sampler2D u_texture;
 varying vec2 v_st0;
 
 void main() {
-    vec2 st = vec2(v_st0.s, 1.0 - v_st0.t);
-    gl_FragColor = texture2D(u_texture, st);
+    gl_FragColor = texture2D(u_texture, v_st0);
 }

samples/bin/library/model_shader.vert

@@ -6,7 +6,11 @@ attribute vec2 a_st0;
 
 varying vec2 v_st0;
 
-void main() {
-    v_st0 = a_st0;
-    gl_Position = vec4(a_vertex, 1.0) * u_matrix_m * u_matrix_vp;
+vec4 vertex_to_homo(vec3 pos) {
+    return vec4(pos, 1.0) * u_matrix_m * u_matrix_vp;
+}
+
+void main() {
+    v_st0 = vec2(a_st0.s, 1.0 - a_st0.t);
+    gl_Position = vertex_to_homo(a_vertex);
 }

samples/bin/library/scene_prefab.json

@@ -22,6 +22,9 @@
     }, {
         "prototype" : "ship_prefab.json",
         "components" : {
+            "sprite_renderer" : {
+                "tint" : [255,0,0,255]
+            },
             "actor" : {
                 "translation" : [50,-50,0]
             }
@@ -31,7 +34,9 @@
         "components" : {
             "label" : {
                 "text" : "bm font",
-                "valign" : "center"
+                "valign" : "center",
+                "outline_width" : 0.5,
+                "outline_color" : [0,0,0,255]
             },
             "actor" : {
                 "translation" : [0,180,0],
@@ -44,11 +49,11 @@
             "label" : {
                 "text" : "sdf font",
                 "valign" : "center",
-                "outline_width" : 0.2,
+                "outline_width" : 0.5,
                 "outline_color" : [0,0,0,255]
             },
             "actor" : {
-                "translation" : [0,-180,0],
+                "translation" : [0.5,-180.5,0],
                 "scale" : 3
             }
         }

samples/bin/library/sprite_material.json

@@ -3,7 +3,7 @@
         "shader" : "sprite_shader.json",
         "state_block" : {
             "blending_state" : {
-                "src_factor" : "src_alpha",
+                "src_factor" : "one",
                 "dst_factor" : "one_minus_src_alpha"
             },
             "capabilities_state" : {

samples/bin/library/sprite_shader.frag

@@ -1,9 +1,10 @@
 uniform sampler2D u_texture;
 
-varying vec4 v_tint;
-varying vec2 v_st;
+varying vec2 v_st0;
+varying vec4 v_color0;
 
 void main() {
-    vec2 st = vec2(v_st.s, 1.0 - v_st.t);
-    gl_FragColor = texture2D(u_texture, st) * v_tint;
+    vec4 c = texture2D(u_texture, v_st0) * v_color0;
+    c.rgb *= c.a;
+    gl_FragColor = c;
 }

samples/bin/library/sprite_shader.vert

@@ -1,14 +1,36 @@
+uniform vec2 u_screen_s;
 uniform mat4 u_matrix_vp;
 
 attribute vec3 a_vertex;
-attribute vec4 a_tint;
-attribute vec2 a_st;
+attribute vec2 a_st0;
+attribute vec4 a_color0;
 
-varying vec4 v_tint;
-varying vec2 v_st;
+varying vec2 v_st0;
+varying vec4 v_color0;
+
+vec2 round(vec2 v) {
+    return vec2(
+        floor(v.x + 0.5),
+        floor(v.y + 0.5));
+}
+
+vec4 pixel_snap(vec4 pos) {
+    vec2 hpc = u_screen_s * 0.5;
+    vec2 pixel_pos = round((pos.xy / pos.w) * hpc);
+    pos.xy = pixel_pos / hpc * pos.w;
+    return pos;
+}
+
+vec4 vertex_to_homo(vec3 pos) {
+    return vec4(pos, 1.0) * u_matrix_vp;
+}
 
 void main() {
-    v_st = a_st;
-    v_tint = a_tint;
-    gl_Position = vec4(a_vertex, 1.0) * u_matrix_vp;
+    v_st0 = vec2(a_st0.s, 1.0 - a_st0.t);
+    v_color0 = a_color0;
+#ifndef VERTEX_SNAPPING_ON
+    gl_Position = vertex_to_homo(a_vertex);
+#else
+    gl_Position = pixel_snap(vertex_to_homo(a_vertex));
+#endif
 }

sources/enduro2d/high/systems/render_system.cpp

@@ -99,7 +99,7 @@ namespace e2d
     class render_system::internal_state final : private noncopyable {
     public:
         internal_state()
-        : drawer_(the<engine>(), the<debug>(), the<render>()) {}
+        : drawer_(the<engine>(), the<debug>(), the<render>(), the<window>()) {}
         ~internal_state() noexcept = default;
 
         void process(ecs::registry& owner) {

sources/enduro2d/high/systems/render_system_impl/render_system_base.hpp

@@ -40,8 +40,8 @@ namespace e2d::render_system_impl
         static vertex_declaration decl() noexcept {
             return vertex_declaration()
                 .add_attribute<v3f>("a_vertex")
-                .add_attribute<v2f>("a_st")
-                .add_attribute<color32>("a_tint").normalized();
+                .add_attribute<v2f>("a_st0")
+                .add_attribute<color32>("a_color0").normalized();
         }
     };
 }

sources/enduro2d/high/systems/render_system_impl/render_system_drawer.cpp

@@ -14,6 +14,7 @@ namespace
 {
     using namespace e2d;
 
+    const str_hash screen_s_property_hash = "u_screen_s";
     const str_hash matrix_v_property_hash = "u_matrix_v";
     const str_hash matrix_p_property_hash = "u_matrix_p";
     const str_hash matrix_vp_property_hash = "u_matrix_vp";
@@ -32,6 +33,7 @@ namespace e2d::render_system_impl
         const const_node_iptr& cam_n,
         engine& engine,
         render& render,
+        window& window,
         batcher_type& batcher)
     : render_(render)
     , batcher_(batcher)
@@ -47,6 +49,9 @@ namespace e2d::render_system_impl
         const m4f& m_p = cam.projection();
 
         batcher_.flush()
+            .property(screen_s_property_hash, cam.target()
+                ? cam.target()->size().cast_to<f32>()
+                : window.framebuffer_size().cast_to<f32>())
             .property(matrix_v_property_hash, m_v)
             .property(matrix_p_property_hash, m_p)
             .property(matrix_vp_property_hash, m_v * m_p)
@@ -219,8 +224,9 @@ namespace e2d::render_system_impl
     // drawer
     //
 
-    drawer::drawer(engine& e, debug& d, render& r)
+    drawer::drawer(engine& e, debug& d, render& r, window& w)
     : engine_(e)
     , render_(r)
+    , window_(w)
     , batcher_(d, r) {}
 }

sources/enduro2d/high/systems/render_system_impl/render_system_drawer.hpp

@@ -36,6 +36,7 @@ namespace e2d::render_system_impl
                 const const_node_iptr& cam_n,
                 engine& engine,
                 render& render,
+                window& window,
                 batcher_type& batcher);
             ~context() noexcept;
 
@@ -59,13 +60,14 @@ namespace e2d::render_system_impl
             render::property_block property_cache_;
         };
     public:
-        drawer(engine& e, debug& d, render& r);
+        drawer(engine& e, debug& d, render& r, window& w);
 
         template < typename F >
         void with(const camera& cam, const const_node_iptr& cam_n, F&& f);
     private:
         engine& engine_;
         render& render_;
+        window& window_;
         batcher_type batcher_;
     };
 }
@@ -74,7 +76,7 @@ namespace e2d::render_system_impl
 {
     template < typename F >
     void drawer::with(const camera& cam, const const_node_iptr& cam_n, F&& f) {
-        context ctx{cam, cam_n, engine_, render_, batcher_};
+        context ctx{cam, cam_n, engine_, render_, window_, batcher_};
         std::forward<F>(f)(ctx);
         ctx.flush();
     }