evas filter: Implement grayscale filter in pure GL

Summary:
Initial version implementing grayscale filter in pure GL.
This patch needs a logt of love as 5bce712 did.

Grasyscale formula:
https://www.tutorialspoint.com/dip/grayscale_to_rgb_conversion.htm

Test Plan:
1. Create filter_example with following .
efl_gfx_filter_program_set(image, "grayscale ()", "grayscale");

2. Run.
ELM_ACCEL=gl ./filter_example

Reviewers: Hermet, jsuya

Subscribers: ali.alzyod, cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D9858

12 files changed, 237 insertions, 2 deletions

diff --git a/src/lib/evas/filters/evas_filter.c b/src/lib/evas/filters/evas_filter.c
index 332f6dbb27..36c9c5d2b1 100644
--- a/src/lib/evas/filters/evas_filter.c
+++ b/src/lib/evas/filters/evas_filter.c
@@ -1597,6 +1597,28 @@ evas_filter_command_transform_add(Evas_Filter_Context *ctx,
    return cmd;
 }
 
+Evas_Filter_Command *
+evas_filter_command_grayscale_add(Evas_Filter_Context *ctx,
+                                  void *draw_context EINA_UNUSED,
+                                  int inbuf, int outbuf)
+{
+   Evas_Filter_Command *cmd;
+   Evas_Filter_Buffer *in, *out;
+
+   EINA_SAFETY_ON_NULL_RETURN_VAL(ctx, NULL);
+
+   in = _filter_buffer_get(ctx, inbuf);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(in, NULL);
+
+   out = _filter_buffer_get(ctx, outbuf);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(out, NULL);
+
+   cmd = _command_new(ctx, EVAS_FILTER_MODE_GRAYSCALE, in, NULL, out);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(out, NULL);
+
+   return cmd;
+}
+
 void
 evas_filter_context_obscured_region_set(Evas_Filter_Context *ctx, Eina_Rectangle rect)
 {
diff --git a/src/lib/evas/filters/evas_filter_parser.c b/src/lib/evas/filters/evas_filter_parser.c
index 72308d2a9e..6d89a3518f 100644
--- a/src/lib/evas/filters/evas_filter_parser.c
+++ b/src/lib/evas/filters/evas_filter_parser.c
@@ -1789,6 +1789,26 @@ _transform_instruction_prepare(Evas_Filter_Program *pgm, Evas_Filter_Instruction
    return EINA_TRUE;
 }
 
+/**
+  @page evasfiltersref
+  Remove color information from buffer's contents and leave only grayscale
+  TODO: write down more information
+ */
+
+static Eina_Bool
+_grayscale_instruction_prepare(Evas_Filter_Program *pgm, Evas_Filter_Instruction *instr)
+{
+   EINA_SAFETY_ON_NULL_RETURN_VAL(instr, EINA_FALSE);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(instr->name, EINA_FALSE);
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(!strcasecmp(instr->name, "grayscale"), EINA_FALSE);
+
+   instr->type = EVAS_FILTER_MODE_GRAYSCALE;
+   _instruction_param_seq_add(instr, "src", VT_BUFFER, _buffer_get(pgm, "input"));
+   _instruction_param_seq_add(instr, "dst", VT_BUFFER, _buffer_get(pgm, "output"));
+
+   return EINA_TRUE;
+}
+
 static int
 _padding_set_padding_update(Evas_Filter_Program *pgm,
                             Evas_Filter_Instruction *instr,
@@ -2249,6 +2269,7 @@ LUA_GENERIC_FUNCTION(grow)
 LUA_GENERIC_FUNCTION(mask)
 LUA_GENERIC_FUNCTION(padding_set)
 LUA_GENERIC_FUNCTION(transform)
+LUA_GENERIC_FUNCTION(grayscale)
 
 static const luaL_Reg _lua_buffer_metamethods[] = {
    { "__call", _lua_buffer_new },
@@ -2485,6 +2506,7 @@ _lua_state_create(Evas_Filter_Program *pgm)
    PUSH_LUA_FUNCTION(mask)
    PUSH_LUA_FUNCTION(padding_set)
    PUSH_LUA_FUNCTION(transform)
+   PUSH_LUA_FUNCTION(grayscale)
 
    for (unsigned k = 0; k < (sizeof(fill_modes) / sizeof(fill_modes[0])); k++)
      {
@@ -3403,6 +3425,20 @@ _instr2cmd_transform(Evas_Filter_Context *ctx,
    return evas_filter_command_transform_add(ctx, dc, src->cid, dst->cid, flags, ox, oy);
 }
 
+static Evas_Filter_Command *
+_instr2cmd_grayscale(Evas_Filter_Context *ctx,
+                     Evas_Filter_Instruction *instr, void *dc)
+{
+   Buffer *src, *dst;
+
+   src = _instruction_param_getbuf(instr, "src", NULL);
+   dst = _instruction_param_getbuf(instr, "dst", NULL);
+   INSTR_PARAM_CHECK(src);
+   INSTR_PARAM_CHECK(dst);
+
+   return evas_filter_command_grayscale_add(ctx, dc, src->cid, dst->cid);
+}
+
 static Eina_Bool
 _command_from_instruction(Evas_Filter_Context *ctx,
                           Evas_Filter_Instruction *instr, void *dc)
@@ -3439,6 +3475,9 @@ _command_from_instruction(Evas_Filter_Context *ctx,
       case EVAS_FILTER_MODE_TRANSFORM:
         instr2cmd = _instr2cmd_transform;
         break;
+      case EVAS_FILTER_MODE_GRAYSCALE:
+        instr2cmd = _instr2cmd_grayscale;
+        break;
       case EVAS_FILTER_MODE_PADDING_SET:
       case EVAS_FILTER_MODE_BUFFER:
         return EINA_TRUE;
diff --git a/src/lib/evas/include/evas_filter.h b/src/lib/evas/include/evas_filter.h
index ffbe797a6d..8dab0a9a34 100644
--- a/src/lib/evas/include/evas_filter.h
+++ b/src/lib/evas/include/evas_filter.h
@@ -69,6 +69,7 @@ enum _Evas_Filter_Mode
    EVAS_FILTER_MODE_BUMP,         /**< Apply bump mapping (light effect) */
    EVAS_FILTER_MODE_TRANSFORM,    /**< Apply a simple geometrical transformation */
    EVAS_FILTER_MODE_PADDING_SET,  /**< Special padding_set instruction to force a specific padding value */
+   EVAS_FILTER_MODE_GRAYSCALE,    /**< Leave only grayscale information */
    EVAS_FILTER_MODE_LAST
 };
 
@@ -306,6 +307,17 @@ Evas_Filter_Command     *evas_filter_command_bump_map_add(Evas_Filter_Context *c
  */
 Evas_Filter_Command     *evas_filter_command_transform_add(Evas_Filter_Context *ctx, void *draw_context, int inbuf, int outbuf, Evas_Filter_Transform_Flags flags, int ox, int oy);
 
+/**
+ * @brief Remove color information from the buffer
+ * @param ctx            Current filter chain
+ * @param draw_context   Current Evas draw context (ignored)
+ * @param inbuf          Input buffer (Alpha or RGBA)
+ * @param outbuf         Output buffer (Alpha or RGBA), same size as inbuf
+ * @return               Filter command or NULL in case of error
+ * @internal
+ */
+Evas_Filter_Command     *evas_filter_command_grayscale_add(Evas_Filter_Context *ctx, void *draw_context, int inbuf, int outbuf);
+
 /* Simple binding between a filter object and its sources */
 struct _Evas_Filter_Proxy_Binding
 {
diff --git a/src/modules/evas/engines/gl_common/evas_gl_common.h b/src/modules/evas/engines/gl_common/evas_gl_common.h
index 2c74423f26..b2cf74bee5 100644
--- a/src/modules/evas/engines/gl_common/evas_gl_common.h
+++ b/src/modules/evas/engines/gl_common/evas_gl_common.h
@@ -265,7 +265,8 @@ enum _Shader_Type {
    SHD_FILTER_DISPLACE,
    SHD_FILTER_CURVE,
    SHD_FILTER_BLUR_X,
-   SHD_FILTER_BLUR_Y
+   SHD_FILTER_BLUR_Y,
+   SHD_FILTER_GRAYSCALE
 };
 
 #define ARRAY_BUFFER_USE 500
@@ -680,6 +681,7 @@ void              evas_gl_common_filter_curve_push(Evas_Engine_GL_Context *gc, E
 void              evas_gl_common_filter_blur_push(Evas_Engine_GL_Context *gc, Evas_GL_Texture *tex, double sx, double sy, double sw, double sh,
                                                   double dx, double dy, double dw, double dh, const double * const values, const double * const offsets, int count, double radius,
                                                   Eina_Bool horiz, Eina_Bool alphaonly);
+void              evas_gl_common_filter_grayscale_push(Evas_Engine_GL_Context *gc, Evas_GL_Texture *tex, int x, int y, int w, int h);
 
 int               evas_gl_common_shader_program_init(Evas_GL_Shared *shared);
 void              evas_gl_common_shader_program_shutdown(Evas_GL_Shared *shared);
diff --git a/src/modules/evas/engines/gl_common/evas_gl_context.c b/src/modules/evas/engines/gl_common/evas_gl_context.c
index bf7e5c1524..9178d3f6b8 100644
--- a/src/modules/evas/engines/gl_common/evas_gl_context.c
+++ b/src/modules/evas/engines/gl_common/evas_gl_context.c
@@ -3679,6 +3679,98 @@ evas_gl_common_filter_blur_push(Evas_Engine_GL_Context *gc,
      PUSH_6_COLORS(pn, r, g, b, a);
 }
 
+void
+evas_gl_common_filter_grayscale_push(Evas_Engine_GL_Context *gc,
+                                Evas_GL_Texture *tex,
+                                int x, int y, int w, int h)
+{
+   double ox1, oy1, ox2, oy2, ox3, oy3, ox4, oy4, pw, ph;
+   GLfloat tx1, ty1, tx2, ty2, tx3, ty3, tx4, ty4;
+   GLfloat offsetx, offsety;
+   int r, g, b, a, nomul = 0, pn;
+   Evas_GL_Program *prog;
+   Eina_Bool blend = EINA_TRUE;
+   Eina_Bool smooth = EINA_TRUE;
+   Shader_Type type = SHD_FILTER_GRAYSCALE;
+
+   r = R_VAL(&gc->dc->mul.col);
+   g = G_VAL(&gc->dc->mul.col);
+   b = B_VAL(&gc->dc->mul.col);
+   a = A_VAL(&gc->dc->mul.col);
+   if (gc->dc->render_op == EVAS_RENDER_COPY)
+     blend = EINA_FALSE;
+
+   prog = evas_gl_common_shader_program_get(gc, type, NULL, 0, r, g, b, a,
+                                            w, h, w, h, smooth, tex, EINA_FALSE,
+                                            NULL, EINA_FALSE, EINA_FALSE, 0, 0,
+                                            EINA_FALSE, NULL, &nomul, NULL);
+
+   _filter_data_flush(gc, prog);
+   EINA_SAFETY_ON_NULL_RETURN(prog);
+
+   pn = _evas_gl_common_context_push(type, gc, tex, NULL, prog,
+                                     x, y, w, h, blend, smooth,
+                                     0, 0, 0, 0, 0, EINA_FALSE);
+
+   gc->pipe[pn].region.type = type;
+   gc->pipe[pn].shader.prog = prog;
+   gc->pipe[pn].shader.cur_tex = tex->pt->texture;
+   gc->pipe[pn].shader.cur_texm = 0;
+   gc->pipe[pn].shader.tex_target = GL_TEXTURE_2D;
+   gc->pipe[pn].shader.smooth = smooth;
+   gc->pipe[pn].shader.mask_smooth = 0;
+   gc->pipe[pn].shader.blend = blend;
+   gc->pipe[pn].shader.render_op = gc->dc->render_op;
+   gc->pipe[pn].shader.clip = 0;
+   gc->pipe[pn].shader.cx = 0;
+   gc->pipe[pn].shader.cy = 0;
+   gc->pipe[pn].shader.cw = 0;
+   gc->pipe[pn].shader.ch = 0;
+   gc->pipe[pn].array.line = 0;
+   gc->pipe[pn].array.use_vertex = 1;
+   gc->pipe[pn].array.use_color = !nomul;
+   gc->pipe[pn].array.use_texuv = 1;
+   gc->pipe[pn].array.use_texuv2 = 0;
+   gc->pipe[pn].array.use_texuv3 = 0;
+   gc->pipe[pn].array.use_texsam = 0;
+   gc->pipe[pn].array.use_mask = 0;
+   gc->pipe[pn].array.use_masksam = 0;
+
+   pipe_region_expand(gc, pn, x, y, w, h);
+   PIPE_GROW(gc, pn, 6);
+
+   _filter_data_alloc(gc, pn, 0);
+
+   pw = tex->pt->w;
+   ph = tex->pt->h;
+
+   ox1 = x;
+   oy1 = y;
+   ox2 = x + w;
+   oy2 = y;
+   ox3 = x + w;
+   oy3 = y + h;
+   ox4 = x;
+   oy4 = y + h;
+
+   offsetx = tex->x;
+   offsety = tex->y;
+
+   tx1 = ((double)(offsetx) + ox1) / pw;
+   ty1 = ((double)(offsety) + oy1) / ph;
+   tx2 = ((double)(offsetx) + ox2) / pw;
+   ty2 = ((double)(offsety) + oy2) / ph;
+   tx3 = ((double)(offsetx) + ox3) / pw;
+   ty3 = ((double)(offsety) + oy3) / ph;
+   tx4 = ((double)(offsetx) + ox4) / pw;
+   ty4 = ((double)(offsety) + oy4) / ph;
+
+   PUSH_6_VERTICES(pn, x, y, w, h);
+   PUSH_6_QUAD(pn, tx1, ty1, tx2, ty2, tx3, ty3, tx4, ty4);
+
+   if (!nomul)
+     PUSH_6_COLORS(pn, r, g, b, a);
+}
 // ----------------------------------------------------------------------------
 
 EAPI void
diff --git a/src/modules/evas/engines/gl_common/evas_gl_shader.c b/src/modules/evas/engines/gl_common/evas_gl_shader.c
index a4dd632896..7c338674ec 100644
--- a/src/modules/evas/engines/gl_common/evas_gl_shader.c
+++ b/src/modules/evas/engines/gl_common/evas_gl_shader.c
@@ -45,8 +45,9 @@ typedef enum {
    SHADER_FLAG_FILTER_BLUR       = (1 << 23),
    SHADER_FLAG_FILTER_DIR_Y      = (1 << 24),
    SHADER_FLAG_FILTER_ALPHA_ONLY = (1 << 25),
+   SHADER_FLAG_FILTER_GRAYSCALE  = (1 << 26),
 } Shader_Flag;
-#define SHADER_FLAG_COUNT 26
+#define SHADER_FLAG_COUNT 27
 
 static const char *_shader_flags[SHADER_FLAG_COUNT] = {
    "TEX",
@@ -75,6 +76,7 @@ static const char *_shader_flags[SHADER_FLAG_COUNT] = {
    "FILTER_BLUR",
    "FILTER_DIR_Y",
    "ALPHA_ONLY",
+   "FILTER_GRAYSCALE",
 };
 
 static Eina_Bool compiler_released = EINA_FALSE;
@@ -824,6 +826,9 @@ evas_gl_common_shader_flags_get(Evas_GL_Shared *shared, Shader_Type type,
         flags |= SHADER_FLAG_FILTER_BLUR;
         flags |= SHADER_FLAG_FILTER_DIR_Y;
         break;
+      case SHD_FILTER_GRAYSCALE:
+        flags |= SHADER_FLAG_FILTER_GRAYSCALE;
+        break;
       default:
         CRI("Impossible shader type.");
         return 0;
diff --git a/src/modules/evas/engines/gl_common/shader/evas_gl_shaders.x b/src/modules/evas/engines/gl_common/shader/evas_gl_shaders.x
index 2b071f2316..73ca4bef11 100644
--- a/src/modules/evas/engines/gl_common/shader/evas_gl_shaders.x
+++ b/src/modules/evas/engines/gl_common/shader/evas_gl_shaders.x
@@ -214,6 +214,9 @@ static const char fragment_glsl[] =
    "#ifdef SHD_ALPHA_ONLY\n"
    "   c = vec4(c.a, c.a, c.a, c.a);\n"
    "#endif\n"
+   "#ifdef SHD_FILTER_GRAYSCALE\n"
+   "   c.rgb = 0.3 * c.r + 0.59 * c.g + 0.11 * c.b;\n"
+   "#endif\n"
    "#ifndef SHD_FILTER_BLUR\n"
    "   gl_FragColor =\n"
    "       c\n"
diff --git a/src/modules/evas/engines/gl_common/shader/fragment.glsl b/src/modules/evas/engines/gl_common/shader/fragment.glsl
index 89f306062a..39fccf1119 100644
--- a/src/modules/evas/engines/gl_common/shader/fragment.glsl
+++ b/src/modules/evas/engines/gl_common/shader/fragment.glsl
@@ -230,6 +230,10 @@ vec4 fetch_pixel(float ox, float oy)
    c = vec4(c.a, c.a, c.a, c.a);
 #endif
 
+#ifdef SHD_FILTER_GRAYSCALE
+   c.rgb = 0.3 * c.r + 0.59 * c.g + 0.11 * c.b;
+#endif
+
 #ifndef SHD_FILTER_BLUR
 
    gl_FragColor =
diff --git a/src/modules/evas/engines/gl_generic/evas_engine.c b/src/modules/evas/engines/gl_generic/evas_engine.c
index 4b0a6c735b..3428cf5620 100644
--- a/src/modules/evas/engines/gl_generic/evas_engine.c
+++ b/src/modules/evas/engines/gl_generic/evas_engine.c
@@ -3127,6 +3127,7 @@ _gfx_filter_func_get(Render_Engine_GL_Generic *re, Evas_Filter_Command *cmd)
       case EVAS_FILTER_MODE_FILL: funcptr = gl_filter_fill_func_get(re, cmd); break;
       case EVAS_FILTER_MODE_MASK: funcptr = gl_filter_mask_func_get(re, cmd); break;
       //case EVAS_FILTER_MODE_TRANSFORM: funcptr = gl_filter_transform_func_get(re, cmd); break;
+      case EVAS_FILTER_MODE_GRAYSCALE: funcptr = gl_filter_grayscale_func_get(re, cmd); break;
       default: return NULL;
      }
 
diff --git a/src/modules/evas/engines/gl_generic/filters/gl_engine_filter.h b/src/modules/evas/engines/gl_generic/filters/gl_engine_filter.h
index 9cb59d1969..b1045d019e 100644
--- a/src/modules/evas/engines/gl_generic/filters/gl_engine_filter.h
+++ b/src/modules/evas/engines/gl_generic/filters/gl_engine_filter.h
@@ -17,6 +17,7 @@ GL_Filter_Apply_Func gl_filter_displace_func_get(Render_Engine_GL_Generic *re, E
 GL_Filter_Apply_Func gl_filter_fill_func_get(Render_Engine_GL_Generic *re, Evas_Filter_Command *cmd);
 GL_Filter_Apply_Func gl_filter_mask_func_get(Render_Engine_GL_Generic *re, Evas_Filter_Command *cmd);
 //GL_Filter_Apply_Func gl_filter_transform_func_get(Evas_Filter_Command *cmd);
+GL_Filter_Apply_Func gl_filter_grayscale_func_get(Render_Engine_GL_Generic *re, Evas_Filter_Command *cmd);
 
 #undef DBG
 #undef INF
diff --git a/src/modules/evas/engines/gl_generic/filters/gl_filter_grayscale.c b/src/modules/evas/engines/gl_generic/filters/gl_filter_grayscale.c
new file mode 100644
index 0000000000..3e8ef1e5e0
--- /dev/null
+++ b/src/modules/evas/engines/gl_generic/filters/gl_filter_grayscale.c
@@ -0,0 +1,53 @@
+#include "gl_engine_filter.h"
+
+static Eina_Bool
+_gl_filter_grayscale(Render_Engine_GL_Generic *re, Evas_Filter_Command *cmd)
+{
+   Evas_Engine_GL_Context *gc;
+   Evas_GL_Image *image, *surface;
+   RGBA_Draw_Context *dc_save;
+   int w, h;
+
+   w = cmd->input->w;
+   h = cmd->input->h;
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(w == cmd->output->w, EINA_FALSE);
+   EINA_SAFETY_ON_FALSE_RETURN_VAL(h == cmd->output->h, EINA_FALSE);
+
+   image = evas_ector_buffer_drawable_image_get(cmd->input->buffer);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(image, EINA_FALSE);
+
+   surface = evas_ector_buffer_render_image_get(cmd->output->buffer);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(surface, EINA_FALSE);
+
+   gc = gl_generic_context_find(re, 1);
+   evas_gl_common_context_target_surface_set(gc, surface);
+
+   dc_save = gc->dc;
+   gc->dc = evas_common_draw_context_new();
+   evas_common_draw_context_set_multiplier(gc->dc, cmd->draw.R, cmd->draw.G, cmd->draw.B, cmd->draw.A);
+
+   if (cmd->input == cmd->output)
+     gc->dc->render_op = EVAS_RENDER_COPY;
+   else
+     gc->dc->render_op = _gfx_to_evas_render_op(cmd->draw.rop);
+
+   evas_gl_common_filter_grayscale_push(gc, image->tex, 0, 0, w, h);
+
+   evas_common_draw_context_free(gc->dc);
+   gc->dc = dc_save;
+
+   evas_ector_buffer_engine_image_release(cmd->input->buffer, image);
+   evas_ector_buffer_engine_image_release(cmd->output->buffer, surface);
+
+   return EINA_TRUE;
+}
+
+GL_Filter_Apply_Func
+gl_filter_grayscale_func_get(Render_Engine_GL_Generic *re EINA_UNUSED, Evas_Filter_Command *cmd)
+{
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd, NULL);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd->output, NULL);
+   EINA_SAFETY_ON_NULL_RETURN_VAL(cmd->input, NULL);
+
+   return _gl_filter_grayscale;
+}
diff --git a/src/modules/evas/engines/gl_generic/meson.build b/src/modules/evas/engines/gl_generic/meson.build
index d18e032f7a..86e5c8fedd 100644
--- a/src/modules/evas/engines/gl_generic/meson.build
+++ b/src/modules/evas/engines/gl_generic/meson.build
@@ -12,6 +12,7 @@ engine_src = files([
   join_paths('filters','gl_filter_displace.c'),
   join_paths('filters','gl_filter_fill.c'),
   join_paths('filters','gl_filter_mask.c'),
+  join_paths('filters','gl_filter_grayscale.c'),
 ])
 common_engine_src = [
   'evas_gl_private.h',