3 files changed, 97 insertions, 0 deletions
diff --git a/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.fsh b/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.fsh
new file mode 100644
index 0000000..057f31f
--- /dev/null
+++ b/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.fsh
@@ -0,0 +1,18 @@
+#version 150
+
+#moj_import <fog.glsl>
+
+uniform vec4 ColorModulator;
+uniform float FogStart;
+uniform float FogEnd;
+uniform vec4 FogColor;
+
+in float vertexDistance;
+in vec4 vertexColor;
+
+out vec4 fragColor;
+
+void main() {
+    vec4 color = vertexColor * ColorModulator;
+    fragColor = linear_fog(color, vertexDistance, FogStart, FogEnd, FogColor);
+}
diff --git a/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.json b/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.json
new file mode 100644
index 0000000..0828480
--- /dev/null
+++ b/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.json
@@ -0,0 +1,17 @@
+{
+    "vertex": "firmament_rendertype_lines",
+    "fragment": "firmament_rendertype_lines",
+    "samplers": [
+    ],
+    "uniforms": [
+        { "name": "ModelViewMat", "type": "matrix4x4", "count": 16, "values": [ 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0 ] },
+        { "name": "ProjMat", "type": "matrix4x4", "count": 16, "values": [ 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0 ] },
+        { "name": "ColorModulator", "type": "float", "count": 4, "values": [ 1.0, 1.0, 1.0, 1.0 ] },
+        { "name": "LineWidth", "type": "float", "count": 1, "values": [ 1.0 ] },
+        { "name": "ScreenSize", "type": "float",     "count": 2,  "values": [ 1.0, 1.0 ] },
+        { "name": "FogStart", "type": "float", "count": 1, "values": [ 0.0 ] },
+        { "name": "FogEnd", "type": "float", "count": 1, "values": [ 1.0 ] },
+        { "name": "FogColor", "type": "float", "count": 4, "values": [ 0.0, 0.0, 0.0, 0.0 ] },
+        { "name": "FogShape", "type": "int", "count": 1, "values": [ 0 ] }
+    ]
+}
diff --git a/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.vsh b/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.vsh
new file mode 100644
index 0000000..35892be
--- /dev/null
+++ b/src/main/resources/assets/minecraft/shaders/core/firmament_rendertype_lines.vsh
@@ -0,0 +1,62 @@
+#version 150
+
+#moj_import <fog.glsl>
+
+in vec3 Position;
+in vec4 Color;
+in vec3 Normal;
+
+uniform mat4 ModelViewMat;
+uniform mat4 ProjMat;
+uniform float LineWidth;
+uniform vec2 ScreenSize;
+uniform int FogShape;
+
+out float vertexDistance;
+out vec4 vertexColor;
+
+const float VIEW_SHRINK = 1.0 - (1.0 / 256.0);
+const mat4 VIEW_SCALE = mat4(
+    VIEW_SHRINK, 0.0, 0.0, 0.0,
+    0.0, VIEW_SHRINK, 0.0, 0.0,
+    0.0, 0.0, VIEW_SHRINK, 0.0,
+    0.0, 0.0, 0.0, 1.0
+);
+
+void main() {
+    vec4 linePosStart = ProjMat * VIEW_SCALE * ModelViewMat * vec4(Position, 1.0);
+    vec4 linePosEnd = ProjMat * VIEW_SCALE * ModelViewMat * vec4(Position + Normal, 1.0);
+
+    vec3 ndc1 = linePosStart.xyz / linePosStart.w;
+    vec3 ndc2 = linePosEnd.xyz / linePosEnd.w;
+
+    bool linePosStartBehind = ndc1.z <= -1;
+    bool linePosEndBehind = ndc2.z <= -1;
+
+    if ((linePosStartBehind && linePosEndBehind)) {
+        gl_Position = vec4(-2.0, -2.0, -2.0, 1.0);
+        return; // I don't care for these people
+    }
+    if (linePosStartBehind || linePosEndBehind) {
+        ndc1.z = 0.0;
+        ndc2.z = 0.0;
+        linePosStart.w = 1.0;
+        // TODO: use mx + b to find move the two coordinates around to extend lines
+    }
+
+    vec2 lineScreenDirection = normalize((ndc2.xy - ndc1.xy) * ScreenSize);
+    vec2 lineOffset = vec2(-lineScreenDirection.y, lineScreenDirection.x) * LineWidth / ScreenSize;
+
+    if (lineOffset.x < 0.0) {
+        lineOffset *= -1.0;
+    }
+
+    if (gl_VertexID % 2 == 0) {
+        gl_Position = vec4((ndc1 + vec3(lineOffset, 0.0)) * linePosStart.w, linePosStart.w);
+    } else {
+        gl_Position = vec4((ndc1 - vec3(lineOffset, 0.0)) * linePosStart.w, linePosStart.w);
+    }
+
+    vertexDistance = fog_distance(Position, FogShape);
+    vertexColor = Color;
+}