From 74fa2828cb7bee6a29931dcedcb9a06b2688d243 Mon Sep 17 00:00:00 2001
From: Omar Rizwan <omar@omar.website>
Date: Tue, 26 Sep 2023 20:48:49 -0400
Subject: display: Basic image support (no rotation/scale yet + cache is hack)

Fix various stride bugs with iamge copying/rechanneling.
---
 virtual-programs/display.folk | 34 +++++++++++++++++++++++++++++++++-
 virtual-programs/images.folk  | 26 ++++++++++++++++----------
 2 files changed, 49 insertions(+), 11 deletions(-)

(limited to 'virtual-programs')

diff --git a/virtual-programs/display.folk b/virtual-programs/display.folk
index 30b9e408..ef24c9d8 100644
--- a/virtual-programs/display.folk
+++ b/virtual-programs/display.folk
@@ -301,7 +301,39 @@ On process {
             }
         }
 
-        proc image {x y im radians {scale 1.0}} {}
+        variable image [Gpu::pipeline {sampler2D image vec2 imageSize
+                                       vec2 pos float radians float scale} {
+            vec2 a = pos - imageSize/2;
+            vec2 b = pos + vec2(imageSize.x, -imageSize.y)/2;
+            vec2 c = pos + imageSize/2;
+            vec2 d = pos + vec2(-imageSize.x, imageSize.y)/2;
+            vec2 vertices[4] = vec2[4](a, b, d, c);
+            return vertices[gl_VertexIndex];
+        } {fn invBilinear} {
+            vec2 a = pos - imageSize/2;
+            vec2 b = pos + vec2(imageSize.x, -imageSize.y)/2;
+            vec2 c = pos + imageSize/2;
+            vec2 d = pos + vec2(-imageSize.x, imageSize.y)/2;
+            vec2 p = gl_FragCoord.xy;
+            vec2 uv = invBilinear(p, a, b, c, d);
+            if( max( abs(uv.x-0.5), abs(uv.y-0.5))<0.5 ) {
+                return texture(samplers[image], uv);
+            }
+            return vec4(0.0, 0.0, 0.0, 0.0);
+        }]
+        variable imCache [dict create]
+        proc image {x y im radians {scale 1.0}} {
+            variable image
+            variable imCache
+            if {![dict exists $imCache $im]} {
+                set gim [Gpu::ImageManager::copyImageToGpu [::image rechannel $im 4]]
+                dict set imCache $im $gim
+            }
+            set gim [dict get $imCache $im]
+            puts $gim
+            Gpu::draw $image $gim [list [::image width $im] [::image height $im]] \
+                [list $x $y] $radians $scale
+        }
 
         proc end {} { Gpu::drawEnd; Gpu::poll }
     }
diff --git a/virtual-programs/images.folk b/virtual-programs/images.folk
index 1d491eec..120b340a 100644
--- a/virtual-programs/images.folk
+++ b/virtual-programs/images.folk
@@ -262,6 +262,8 @@ namespace eval ::image {
         // TODO: Free the PNG.
     }
 
+    # Allocates(!) a copy of `im` with `components` channels. Up to
+    # the caller to free it.
     $cc proc rechannel {image_t im int components} image_t {
         if (im.components == components) return im;
         if (components != 4 || im.components != 3) exit(2);
@@ -270,16 +272,20 @@ namespace eval ::image {
         ret.components = components;
         ret.bytesPerRow = ret.width * ret.components;
         ret.data = folkHeapAlloc(ret.bytesPerRow * ret.height);
-        
-        for(int i = 0; i < ret.width*ret.height; i++) {
-            int r = im.data[i*im.components+0],
-                g = im.data[i*im.components+1], 
-                b = im.data[i*im.components+2];
-
-            ret.data[i*ret.components+0] = r;
-            ret.data[i*ret.components+1] = g;
-            ret.data[i*ret.components+2] = b;
-            ret.data[i*ret.components+3] = 255;
+
+        for (int y = 0; y < im.height; y++) {
+            for (int x = 0; x < im.width; x++) {
+                int imidx = y*im.bytesPerRow + x*im.components;
+                int r = im.data[imidx+0],
+                    g = im.data[imidx+1], 
+                    b = im.data[imidx+2];
+
+                int ridx = y*ret.bytesPerRow + x*ret.components;
+                ret.data[ridx+0] = r;
+                ret.data[ridx+1] = g;
+                ret.data[ridx+2] = b;
+                ret.data[ridx+3] = 255;
+            }
         }
         return ret;
     }
-- 
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