From 3fd33ecff7472e4d6fc9e6b3905f56982e497ef2 Mon Sep 17 00:00:00 2001
From: hachem <im@hachem.wtf>
Date: Sun, 23 Aug 2026 17:21:37 +0200
Subject: [feat]: complete RHI api

---
 assets/shaders/sphere.slang | 74 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 assets/shaders/sphere.slang

(limited to 'assets/shaders/sphere.slang')

diff --git a/assets/shaders/sphere.slang b/assets/shaders/sphere.slang
new file mode 100644
index 0000000..e37700d
--- /dev/null
+++ b/assets/shaders/sphere.slang
@@ -0,0 +1,74 @@
+// Lit sphere (Blinn-Phong + HDRI ambient + selection rim). Uniforms in a
+// ConstantBuffer (UBO, binding 0) so both backends drive it through the RHI;
+// the environment cubemap is a separate sampler at binding 1.
+struct SphereU
+{
+    float4x4 u_ViewProjection;
+    float4x4 u_Transform;
+    float3   u_Color;
+    float    u_Specular;
+    float    u_Emission;
+    float3   u_LightPos;
+    float3   u_CameraPos;
+    int      u_IsSelected;
+    float3   u_OutlineColor;
+    float    u_OutlineWidth;
+};
+ConstantBuffer<SphereU> su;
+
+struct VSInput
+{
+    float3 position : POSITION;
+    float3 normal   : NORMAL;
+};
+
+struct VSOutput
+{
+    float4 position : SV_Position;
+    float3 normal   : TEXCOORD0;
+    float3 worldPos : TEXCOORD1;
+};
+
+[shader("vertex")]
+VSOutput vertexMain(VSInput input)
+{
+    VSOutput output;
+    output.worldPos = mul(su.u_Transform, float4(input.position, 1.0)).xyz;
+    float3x3 normalMatrix = (float3x3)su.u_Transform;
+    output.normal   = mul(normalMatrix, input.normal);
+    output.position = mul(su.u_ViewProjection, float4(output.worldPos, 1.0));
+    return output;
+}
+
+SamplerCube u_HDRIEnvironment;
+
+[shader("fragment")]
+float4 fragmentMain(VSOutput input) : SV_Target
+{
+    float3 normal     = normalize(input.normal);
+    float3 lightDir   = normalize(su.u_LightPos - input.worldPos);
+    float3 viewDir    = normalize(su.u_CameraPos - input.worldPos);
+    float3 reflectDir = reflect(-lightDir, normal);
+
+    float3 hdriLight     = u_HDRIEnvironment.Sample(normal).rgb;
+    float  hdriIntensity = 0.3;
+
+    float diff = max(dot(normal, lightDir), 0.0);
+    float spec = pow(max(dot(viewDir, reflectDir), 0.0), 32.0);
+
+    float3 diffuse  = su.u_Color * (diff + hdriIntensity * hdriLight);
+    float3 specular = float3(su.u_Specular, su.u_Specular, su.u_Specular) * spec;
+    float3 emission = su.u_Color * su.u_Emission;
+
+    float3 result = diffuse + specular + emission;
+
+    if (su.u_IsSelected > 0)
+    {
+        float ndotv       = max(dot(normal, viewDir), 0.0);
+        float rim         = 1.0 - ndotv;
+        float outlineMask = step(1.0 - su.u_OutlineWidth, rim);
+        result = lerp(result, su.u_OutlineColor, outlineMask);
+    }
+
+    return float4(result, 1.0);
+}
-- 
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