From 9afb845a36b0a42470d9ec023b3570730fac2a92 Mon Sep 17 00:00:00 2001
From: shweet <email@shweetz.net>
Date: Sat, 13 Sep 2025 12:28:37 -0400
Subject: [PATCH] add slight texture inset for layer UVs.

---
 src/canvas.h             | 5 +++++
 src/generate_preview.cpp | 5 +++--
 src/preview.cpp          | 5 +++--
 src/texture.cpp          | 2 +-
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/canvas.h b/src/canvas.h
index 17fcbfb..06a9d2f 100644
--- a/src/canvas.h
+++ b/src/canvas.h
@@ -65,6 +65,11 @@ struct Canvas
   0, 1, uvMin.x, uvMax.y  \
 }
 
+#define ATLAS_UV_MIN(type) (ATLAS_POSITION(type) / TEXTURE_ATLAS_SIZE)
+#define ATLAS_UV_MAX(type) ((ATLAS_POSITION(type) + ATLAS_SIZE(type)) / TEXTURE_ATLAS_SIZE)
+#define ATLAS_UV_ARGS(type) ATLAS_UV_MIN(type), ATLAS_UV_MAX(type)
+#define ATLAS_UV_VERTICES(type) UV_VERTICES(ATLAS_UV_MIN(type), ATLAS_UV_MAX(type))
+
 mat4 canvas_transform_get(Canvas* self, vec2 pan, f32 zoom, OriginType origin);
 void canvas_axes_draw(Canvas* self, GLuint& shader, mat4& transform, vec4& color);
 void canvas_bind(Canvas* self);
diff --git a/src/generate_preview.cpp b/src/generate_preview.cpp
index f02aca7..7faa101 100644
--- a/src/generate_preview.cpp
+++ b/src/generate_preview.cpp
@@ -38,8 +38,9 @@ void generate_preview_draw(GeneratePreview* self)
             const s32 column = index % columns;
             vec2 crop = startPosition + vec2(size.x * column, size.y * row);
 
-            vec2 uvMin = crop / vec2(texture.size);
-            vec2 uvMax = (crop + size) / vec2(texture.size);
+            vec2 textureSize = vec2(texture.size);
+            vec2 uvMin = (crop + vec2(0.5f)) / textureSize;
+            vec2 uvMax = (crop + size - vec2(0.5f)) / textureSize;
             f32 vertices[] = UV_VERTICES(uvMin, uvMax);
 
             mat4 generateTransform = transform * quad_model_get(size, {}, pivot);
diff --git a/src/preview.cpp b/src/preview.cpp
index b5610f2..8001854 100644
--- a/src/preview.cpp
+++ b/src/preview.cpp
@@ -134,8 +134,9 @@ void preview_draw(Preview* self)
             Texture& texture = spritesheet->texture;
             if (texture.isInvalid) return;
             
-            vec2 uvMin = frame.crop / vec2(texture.size);
-            vec2 uvMax = (frame.crop + frame.size) / vec2(texture.size);
+            vec2 inset = 0.5f / vec2(texture.size);
+            vec2 uvMin = frame.crop / vec2(texture.size) + inset;
+            vec2 uvMax = (frame.crop + frame.size) / vec2(texture.size) - inset;
             f32 vertices[] = UV_VERTICES(uvMin, uvMax);
             canvas_texture_draw(&self->canvas, shaderTexture, texture.id, layerTransform, vertices, frameTint, frameColorOffset);
 
diff --git a/src/texture.cpp b/src/texture.cpp
index c09424f..8b80bb2 100644
--- a/src/texture.cpp
+++ b/src/texture.cpp
@@ -126,4 +126,4 @@ bool texture_pixel_set(Texture* self, ivec2 position, vec4 color)
     glTexSubImage2D(GL_TEXTURE_2D, 0,position.x, position.y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, rgba8);
 
     return true;
-}
\ No newline at end of file
+}