source/blender/draw/engines/image/image_batches.hh

@@ -46,24 +46,8 @@ class BatchUpdater {
     GPU_batch_init_ex(info.batch, GPU_PRIM_TRI_FAN, vbo, nullptr, GPU_BATCH_OWNS_VBO);
   }
 
-  GPUVertBuf *create_vbo()
-  {
-    GPUVertBuf *vbo = GPU_vertbuf_create_with_format(&format);
-    GPU_vertbuf_data_alloc(vbo, 4);
-    float pos[4][2];
-    fill_tri_fan_from_rctf(pos, info.clipping_bounds);
-    float uv[4][2];
-    fill_tri_fan_from_rctf(uv, info.clipping_uv_bounds);
-
-    for (int i = 0; i < 4; i++) {
-      GPU_vertbuf_attr_set(vbo, pos_id, i, pos[i]);
-      GPU_vertbuf_attr_set(vbo, uv_id, i, uv[i]);
-    }
-
-    return vbo;
-  }
-
-  static void fill_tri_fan_from_rctf(float result[4][2], rctf &rect)
+  template<typename DataType, typename RectType>
+  static void fill_tri_fan_from_rect(DataType result[4][2], RectType &rect)
   {
     result[0][0] = rect.xmin;
     result[0][1] = rect.ymin;
@@ -75,10 +59,27 @@ class BatchUpdater {
     result[3][1] = rect.ymax;
   }
 
+  GPUVertBuf *create_vbo()
+  {
+    GPUVertBuf *vbo = GPU_vertbuf_create_with_format(&format);
+    GPU_vertbuf_data_alloc(vbo, 4);
+    int pos[4][2];
+    fill_tri_fan_from_rect<int, rcti>(pos, info.clipping_bounds);
+    float uv[4][2];
+    fill_tri_fan_from_rect<float, rctf>(uv, info.clipping_uv_bounds);
+
+    for (int i = 0; i < 4; i++) {
+      GPU_vertbuf_attr_set(vbo, pos_id, i, pos[i]);
+      GPU_vertbuf_attr_set(vbo, uv_id, i, uv[i]);
+    }
+
+    return vbo;
+  }
+
   void ensure_format()
   {
     if (format.attr_len == 0) {
-      GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+      GPU_vertformat_attr_add(&format, "pos", GPU_COMP_I32, 2, GPU_FETCH_INT);
       GPU_vertformat_attr_add(&format, "uv", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
 
       pos_id = GPU_vertformat_attr_id_get(&format, "pos");

source/blender/draw/engines/image/image_drawing_mode.hh

@@ -21,11 +21,88 @@ namespace blender::draw::image_engine {
 
 constexpr float EPSILON_UV_BOUNDS = 0.00001f;
 
+class BaseTextureMethod {
+ protected:
+  IMAGE_InstanceData *instance_data;
+
+ protected:
+  BaseTextureMethod(IMAGE_InstanceData *instance_data) : instance_data(instance_data)
+  {
+  }
+
+ public:
+  /**
+   * \brief Ensure enough texture infos are allocated in `instance_data`.
+   */
+  virtual void ensure_texture_infos() = 0;
+
+  /**
+   * \brief Update the uv and region bounds of all texture_infos of instance_data.
+   */
+  virtual void update_bounds(const ARegion *region) = 0;
+
+  virtual void ensure_gpu_textures_allocation() = 0;
+};
+
+/**
+ * Uses a single texture that covers the area. Every zoom/pan change requires a full
+ * update of the texture.
+ */
+class OneTexture : public BaseTextureMethod {
+ public:
+  OneTexture(IMAGE_InstanceData *instance_data) : BaseTextureMethod(instance_data)
+  {
+  }
+  void ensure_texture_infos() override
+  {
+    instance_data->texture_infos.resize(1);
+  }
+
+  void update_bounds(const ARegion *region) override
+  {
+    float4x4 mat = math::invert(float4x4(instance_data->ss_to_texture));
+    float2 region_uv_min = math::transform_point(mat, float3(0.0f, 0.0f, 0.0f)).xy();
+    float2 region_uv_max = math::transform_point(mat, float3(1.0f, 1.0f, 0.0f)).xy();
+
+    TextureInfo &texture_info = instance_data->texture_infos[0];
+    texture_info.tile_id = int2(0);
+    texture_info.need_full_update = false;
+    rctf new_clipping_uv_bounds;
+    BLI_rctf_init(&new_clipping_uv_bounds,
+                  region_uv_min.x,
+                  region_uv_max.x,
+                  region_uv_min.y,
+                  region_uv_max.y);
+
+    if (memcmp(&new_clipping_uv_bounds, &texture_info.clipping_uv_bounds, sizeof(rctf))) {
+      texture_info.clipping_uv_bounds = new_clipping_uv_bounds;
+      texture_info.need_full_update = true;
+    }
+
+    rcti new_clipping_bounds;
+    BLI_rcti_init(&new_clipping_bounds, 0, region->winx, 0, region->winy);
+    if (memcmp(&new_clipping_bounds, &texture_info.clipping_bounds, sizeof(rcti))) {
+      texture_info.clipping_bounds = new_clipping_bounds;
+      texture_info.need_full_update = true;
+    }
+  }
+
+  void ensure_gpu_textures_allocation() override
+  {
+    TextureInfo &texture_info = instance_data->texture_infos[0];
+    int2 texture_size = int2(BLI_rcti_size_x(&texture_info.clipping_bounds),
+                             BLI_rcti_size_y(&texture_info.clipping_bounds));
+    texture_info.ensure_gpu_texture(texture_size);
+  }
+};
+
 /**
  * \brief Screen space method using a multiple textures covering the region.
  *
+ * This method improves panning speed, but has some drawing artifacts and
+ * therefore isn't selected.
  */
-template<size_t Divisions> class ScreenTileTextures {
+template<size_t Divisions> class ScreenTileTextures : public BaseTextureMethod {
  public:
   static const size_t TexturesPerDimension = Divisions + 1;
   static const size_t TexturesRequired = TexturesPerDimension * TexturesPerDimension;
@@ -38,19 +115,19 @@ template<size_t Divisions> class ScreenTileTextures {
   struct TextureInfoBounds {
     TextureInfo *info = nullptr;
     rctf uv_bounds;
+    /* Offset of this tile to be drawn on the screen (number of tiles from bottom left corner). */
+    int2 tile_id;
   };
 
-  IMAGE_InstanceData *instance_data;
-
  public:
-  ScreenTileTextures(IMAGE_InstanceData *instance_data) : instance_data(instance_data)
+  ScreenTileTextures(IMAGE_InstanceData *instance_data) : BaseTextureMethod(instance_data)
   {
   }
 
   /**
    * \brief Ensure enough texture infos are allocated in `instance_data`.
    */
-  void ensure_texture_infos()
+  void ensure_texture_infos() override
   {
     instance_data->texture_infos.resize(TexturesRequired);
   }
@@ -58,7 +135,7 @@ template<size_t Divisions> class ScreenTileTextures {
   /**
    * \brief Update the uv and region bounds of all texture_infos of instance_data.
    */
-  void update_bounds(const ARegion *region)
+  void update_bounds(const ARegion *region) override
   {
     /* determine uv_area of the region. */
     Vector<TextureInfo *> unassigned_textures;
@@ -78,13 +155,22 @@ template<size_t Divisions> class ScreenTileTextures {
     rctf region_uv_bounds;
     BLI_rctf_init(
         &region_uv_bounds, region_uv_min.x, region_uv_max.x, region_uv_min.y, region_uv_max.y);
-    update_region_bounds_from_uv_bounds(region_uv_bounds, float2(region->winx, region->winy));
+    update_region_bounds_from_uv_bounds(region_uv_bounds, int2(region->winx, region->winy));
   }
 
-  void ensure_gpu_textures_allocation()
+  /**
+   * Get the texture size of a single texture for the current settings.
+   */
+  int2 gpu_texture_size() const
   {
     float2 viewport_size = DRW_viewport_size_get();
     int2 texture_size(ceil(viewport_size.x / Divisions), ceil(viewport_size.y / Divisions));
+    return texture_size;
+  }
+
+  void ensure_gpu_textures_allocation() override
+  {
+    int2 texture_size = gpu_texture_size();
     for (TextureInfo &info : instance_data->texture_infos) {
       info.ensure_gpu_texture(texture_size);
     }
@@ -109,6 +195,7 @@ template<size_t Divisions> class ScreenTileTextures {
     for (int x = 0; x < TexturesPerDimension; x++) {
       for (int y = 0; y < TexturesPerDimension; y++) {
         TextureInfoBounds texture_info_bounds;
+        texture_info_bounds.tile_id = int2(x, y);
         BLI_rctf_init(&texture_info_bounds.uv_bounds,
                       uv_coords[x][y].x,
                       uv_coords[x + 1][y + 1].x,
@@ -129,6 +216,7 @@ template<size_t Divisions> class ScreenTileTextures {
         if (info_bound.info == nullptr &&
             BLI_rctf_compare(&info_bound.uv_bounds, &info.clipping_uv_bounds, 0.001)) {
           info_bound.info = &info;
+          info.tile_id = info_bound.tile_id;
           assigned = true;
           break;
         }
@@ -145,20 +233,34 @@ template<size_t Divisions> class ScreenTileTextures {
     for (TextureInfoBounds &info_bound : info_bounds) {
       if (info_bound.info == nullptr) {
         info_bound.info = unassigned_textures.pop_last();
+        info_bound.info->tile_id = info_bound.tile_id;
         info_bound.info->need_full_update = true;
         info_bound.info->clipping_uv_bounds = info_bound.uv_bounds;
       }
     }
   }
 
-  void update_region_bounds_from_uv_bounds(const rctf &region_uv_bounds, const float2 region_size)
+  void update_region_bounds_from_uv_bounds(const rctf &region_uv_bounds, const int2 region_size)
   {
     rctf region_bounds;
     BLI_rctf_init(&region_bounds, 0.0, region_size.x, 0.0, region_size.y);
     float4x4 uv_to_screen;
     BLI_rctf_transform_calc_m4_pivot_min(&region_uv_bounds, &region_bounds, uv_to_screen.ptr());
+    int2 tile_origin(0);
+    for (const TextureInfo &info : instance_data->texture_infos) {
+      if (info.tile_id == int2(0)) {
+        tile_origin = int2(math::transform_point(
+            uv_to_screen,
+            float3(info.clipping_uv_bounds.xmin, info.clipping_uv_bounds.ymin, 0.0)));
+        break;
+      }
+    }
+
+    const int2 texture_size = gpu_texture_size();
     for (TextureInfo &info : instance_data->texture_infos) {
-      info.update_region_bounds_from_uv_bounds(uv_to_screen);
+      int2 bottom_left = tile_origin + texture_size * info.tile_id;
+      int2 top_right = bottom_left + texture_size;
+      BLI_rcti_init(&info.clipping_bounds, bottom_left.x, top_right.x, bottom_left.y, top_right.y);
     }
   }
 };
@@ -498,7 +600,7 @@ template<typename TextureMethod> class ScreenSpaceDrawingMode : public AbstractD
         tile_buffer.y * (texture_info.clipping_uv_bounds.ymin - image_tile.get_tile_y_offset()),
         tile_buffer.y * (texture_info.clipping_uv_bounds.ymax - image_tile.get_tile_y_offset()));
     BLI_rctf_transform_calc_m4_pivot_min(&tile_area, &texture_area, uv_to_texel.ptr());
-    invert_m4(uv_to_texel.ptr());
+    uv_to_texel = math::invert(uv_to_texel);
 
     rctf crop_rect;
     rctf *crop_rect_ptr = nullptr;
@@ -585,6 +687,6 @@ template<typename TextureMethod> class ScreenSpaceDrawingMode : public AbstractD
     DRW_view_set_active(nullptr);
     GPU_framebuffer_bind(dfbl->default_fb);
   }
-};  // namespace clipping
+};
 
 }  // namespace blender::draw::image_engine

source/blender/draw/engines/image/image_engine.cc

@@ -53,7 +53,7 @@ template<
      *
      * Useful during development to switch between drawing implementations.
      */
-    typename DrawingMode = ScreenSpaceDrawingMode<ScreenTileTextures<1>>>
+    typename DrawingMode = ScreenSpaceDrawingMode<OneTexture>>
 class ImageEngine {
  private:
   const DRWContextState *draw_ctx;

source/blender/draw/engines/image/image_texture_info.hh

@@ -24,15 +24,19 @@ struct TextureInfo {
   bool need_full_update : 1;
 
   /** \brief area of the texture in screen space. */
-  rctf clipping_bounds;
+  rcti clipping_bounds;
   /** \brief uv area of the texture in screen space. */
   rctf clipping_uv_bounds;
 
+  /* Which tile of the screen is used with this texture. Used to safely calculate the correct
+   * offset of the textures. */
+  int2 tile_id;
+
   /**
    * \brief Batch to draw the associated text on the screen.
    *
    * Contains a VBO with `pos` and `uv`.
-   * `pos` (2xF32) is relative to the origin of the space.
+   * `pos` (2xI32) is relative to the origin of the space.
    * `uv` (2xF32) reflect the uv bounds.
    */
   GPUBatch *batch = nullptr;
@@ -68,22 +72,6 @@ struct TextureInfo {
     return int2(clipping_bounds.xmin, clipping_bounds.ymin);
   }
 
-  /**
-   * \brief Update the region bounds from the uv bounds by applying the given transform matrix.
-   */
-  void update_region_bounds_from_uv_bounds(const float4x4 &uv_to_region)
-  {
-    float3 bottom_left_uv = float3(clipping_uv_bounds.xmin, clipping_uv_bounds.ymin, 0.0f);
-    float3 top_right_uv = float3(clipping_uv_bounds.xmax, clipping_uv_bounds.ymax, 0.0f);
-    float3 bottom_left_region = math::transform_point(uv_to_region, bottom_left_uv);
-    float3 top_right_region = math::transform_point(uv_to_region, top_right_uv);
-    BLI_rctf_init(&clipping_bounds,
-                  bottom_left_region.x,
-                  top_right_region.x,
-                  bottom_left_region.y,
-                  top_right_region.y);
-  }
-
   void ensure_gpu_texture(int2 texture_size)
   {
     const bool is_allocated = texture != nullptr;

source/blender/draw/engines/image/shaders/image_engine_color_vert.glsl

@@ -2,10 +2,9 @@
 
 void main()
 {
-  vec3 image_pos = vec3(pos, 0.0);
+  vec3 image_pos = vec3(pos.x, pos.y, 0.0);
   uv_screen = image_pos.xy;
 
-  vec3 world_pos = point_object_to_world(image_pos);
-  vec4 position = point_world_to_ndc(world_pos);
+  vec4 position = point_world_to_ndc(image_pos);
   gl_Position = position;
 }

source/blender/draw/engines/image/shaders/image_engine_depth_vert.glsl

@@ -2,10 +2,9 @@
 
 void main()
 {
-  vec3 image_pos = vec3(pos, 0.0);
+  vec3 image_pos = vec3(pos.x, pos.y, 0.0);
   uv_image = uv;
 
-  vec3 world_pos = point_object_to_world(image_pos);
-  vec4 position = point_world_to_ndc(world_pos);
+  vec4 position = point_world_to_ndc(image_pos);
   gl_Position = position;
 }

source/blender/draw/engines/image/shaders/infos/engine_image_info.hh

@@ -5,7 +5,7 @@
 GPU_SHADER_INTERFACE_INFO(image_engine_color_iface, "").smooth(Type::VEC2, "uv_screen");
 
 GPU_SHADER_CREATE_INFO(image_engine_color_shader)
-    .vertex_in(0, Type::VEC2, "pos")
+    .vertex_in(0, Type::IVEC2, "pos")
     .vertex_out(image_engine_color_iface)
     .fragment_out(0, Type::VEC4, "fragColor")
     .push_constant(Type::VEC4, "shuffle")
@@ -23,7 +23,7 @@ GPU_SHADER_CREATE_INFO(image_engine_color_shader)
 GPU_SHADER_INTERFACE_INFO(image_engine_depth_iface, "").smooth(Type::VEC2, "uv_image");
 
 GPU_SHADER_CREATE_INFO(image_engine_depth_shader)
-    .vertex_in(0, Type::VEC2, "pos")
+    .vertex_in(0, Type::IVEC2, "pos")
     .vertex_in(1, Type::VEC2, "uv")
     .vertex_out(image_engine_depth_iface)
     .push_constant(Type::VEC4, "min_max_uv")