lib/gamnit depth: TextureMaterial supports subtexture

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/gamnit/depth/more_materials.nit b/lib/gamnit/depth/more_materials.nit
index 453c7e4..27bdd9a 100644 (file)
--- a/lib/gamnit/depth/more_materials.nit
+++ b/lib/gamnit/depth/more_materials.nit
@@ -102,7 +102,8 @@ class TexturedMaterial
                var program = app.versatile_program
                program.use
 
-               var need_tex_coord = false
+               # One of the textures used, if any
+               var sample_used_texture = null
 
                var texture = ambient_texture
                if texture != null then
@@ -110,7 +111,7 @@ class TexturedMaterial
                        glBindTexture(gl_TEXTURE_2D, texture.gl_texture)
                        program.use_map_ambient.uniform true
                        program.map_ambient.uniform 0
-                       need_tex_coord = true
+                       sample_used_texture = texture
                else
                        program.use_map_ambient.uniform false
                end
@@ -121,7 +122,7 @@ class TexturedMaterial
                        glBindTexture(gl_TEXTURE_2D, texture.gl_texture)
                        program.use_map_diffuse.uniform true
                        program.map_diffuse.uniform 1
-                       need_tex_coord = true
+                       sample_used_texture = texture
                else
                        program.use_map_diffuse.uniform false
                end
@@ -132,7 +133,7 @@ class TexturedMaterial
                        glBindTexture(gl_TEXTURE_2D, texture.gl_texture)
                        program.use_map_specular.uniform true
                        program.map_specular.uniform 2
-                       need_tex_coord = true
+                       sample_used_texture = texture
                else
                        program.use_map_specular.uniform false
                end
@@ -140,8 +141,29 @@ class TexturedMaterial
                program.translation.uniform(actor.center.x, actor.center.y, actor.center.z, 0.0)
                program.scale.uniform actor.scale
 
-               program.tex_coord.array_enabled = need_tex_coord
-               program.tex_coord.array(mesh.texture_coords, 2)
+               # If using a texture, set `texture_coords`
+               program.tex_coord.array_enabled = sample_used_texture != null
+               if sample_used_texture != null then
+                       if sample_used_texture isa GamnitRootTexture then
+                               # Coordinates are directly valid
+                               program.tex_coord.array(mesh.texture_coords, 2)
+                       else
+                               # Correlate texture coordinates from the substexture and the mesh.
+                               # This is slow, but should be cached on the GPU.
+                               var xa = sample_used_texture.offset_left
+                               var xd = sample_used_texture.offset_right - xa
+                               var ya = sample_used_texture.offset_top
+                               var yd = sample_used_texture.offset_bottom - ya
+
+                               var tex_coords = new Array[Float].with_capacity(mesh.texture_coords.length)
+                               for i in [0..mesh.texture_coords.length/2[ do
+                                       tex_coords[i*2]   = xa + xd * mesh.texture_coords[i*2]
+                                       tex_coords[i*2+1] = ya + yd * mesh.texture_coords[i*2+1]
+                               end
+
+                               program.tex_coord.array(tex_coords, 2)
+                       end
+               end
 
                program.coord.array_enabled = true
                program.coord.array(mesh.vertices, 3)