Merge pull request #1 from essial/main

Added basic rendering functionality.

Author: essial

go.mod

@@ -7,4 +7,5 @@ require (
 	github.com/sirupsen/logrus v1.7.0
 	github.com/veandco/go-sdl2 v0.4.5
 	go.uber.org/fx v1.13.1
+	golang.org/x/tools v0.0.0-20191114200427-caa0b0f7d508
 )

internal/engine/backends/graphicsbackend/interface.go

@@ -9,6 +9,10 @@ type Interface interface {
 	GetVSyncEnabled() bool
 	GetCursorPos() (int, int)
 	CurrentFPS() float64
-	// NewSurface(width, height int) Surface
+	NewSurface(width, height int, pixelData *[]byte) (Surface, error)
 	Render() error
 }
+
+type Surface interface {
+	RenderTo(surface Surface) error
+}

internal/engine/backends/graphicsbackend/sdl2graphicsbackend/graphicsbackend.go

@@ -3,6 +3,7 @@ package sdl2graphicsbackend
 import (
 	"github.com/OpenDiablo2/AbyssEngine/internal/engine/backends/graphicsbackend"
 	"github.com/veandco/go-sdl2/sdl"
+	"golang.org/x/tools/go/ssa/interp/testdata/src/errors"
 )
 
 const (
@@ -11,6 +12,7 @@ const (
 )
 
 var _ graphicsbackend.Interface = &SDL2GraphicsBackend{}
+var _ graphicsbackend.Surface = &SDL2GraphicsBackend{}
 
 type SDL2GraphicsBackend struct {
 	window   *sdl.Window
@@ -32,19 +34,31 @@ func Create() (*SDL2GraphicsBackend, error) {
 		return nil, err
 	}
 
-	window, err := sdl.CreateWindow("OpenDiablo 2", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED, 640, 480, sdl.WINDOW_SHOWN|sdl.WINDOW_RESIZABLE|sdl.WINDOW_INPUT_FOCUS)
+	window, err := sdl.CreateWindow("OpenDiablo 2", sdl.WINDOWPOS_UNDEFINED, sdl.WINDOWPOS_UNDEFINED,
+		640, 480, sdl.WINDOW_SHOWN|sdl.WINDOW_RESIZABLE|sdl.WINDOW_INPUT_FOCUS)
+
 	if err != nil {
 		return nil, err
 	}
 
-	r, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED|sdl.RENDERER_TARGETTEXTURE|sdl.RENDERER_PRESENTVSYNC)
+	r, err := sdl.CreateRenderer(window, -1,
+		sdl.RENDERER_ACCELERATED|sdl.RENDERER_TARGETTEXTURE|sdl.RENDERER_PRESENTVSYNC)
+
 	if err != nil {
 		return nil, err
 	}
 
-	r.SetDrawBlendMode(sdl.BLENDMODE_BLEND)
-	r.SetIntegerScale(false)
-	r.SetLogicalSize(800, 600)
+	if err := r.SetDrawBlendMode(sdl.BLENDMODE_BLEND); err != nil {
+		return nil, err
+	}
+
+	if err := r.SetIntegerScale(false); err != nil {
+		return nil, err
+	}
+
+	if err := r.SetLogicalSize(800, 600); err != nil {
+		return nil, err
+	}
 	window.SetMinimumSize(800, 600)
 
 	result := &SDL2GraphicsBackend{
@@ -86,3 +100,26 @@ func (r *SDL2GraphicsBackend) GetCursorPos() (int, int) {
 func (r *SDL2GraphicsBackend) CurrentFPS() float64 {
 	panic("implement me")
 }
+
+func (r *SDL2GraphicsBackend) NewSurface(width, height int, pixelData *[]byte) (graphicsbackend.Surface, error) {
+	var texture *sdl.Texture
+	var err error
+
+	if texture, err = r.renderer.CreateTexture(sdl.PIXELFORMAT_ARGB8888, sdl.TEXTUREACCESS_TARGET,
+		int32(width), int32(height)); err != nil {
+		return nil, err
+	}
+
+	if err = texture.Update(nil, *pixelData, width*4); err != nil {
+		return nil, err
+	}
+
+	result := CreateSDL2Surface(r.renderer, texture, int32(width), int32(height))
+
+	return result, nil
+}
+
+func (r *SDL2GraphicsBackend) RenderTo(graphicsbackend.Surface) error {
+	return errors.New("cannot render the output surface to another surface")
+}
+

internal/engine/backends/graphicsbackend/sdl2graphicsbackend/surface.go

@@ -0,0 +1,47 @@
+package sdl2graphicsbackend
+
+import (
+	"github.com/OpenDiablo2/AbyssEngine/internal/engine/backends/graphicsbackend"
+	"github.com/veandco/go-sdl2/sdl"
+)
+
+var _ graphicsbackend.Surface = &SDL2Surface{}
+
+type SDL2Surface struct {
+	texture       *sdl.Texture
+	width, height int32
+	renderer      *sdl.Renderer
+}
+
+func CreateSDL2Surface(renderer *sdl.Renderer, 	texture *sdl.Texture, width, height int32) *SDL2Surface {
+	result := &SDL2Surface{
+		renderer: renderer,
+		texture:  texture,
+		width:    width,
+		height:   height,
+	}
+
+	return result
+}
+
+func (s SDL2Surface) RenderTo(targetSurface graphicsbackend.Surface) error {
+	sdlTargetSurface := targetSurface.(*SDL2Surface)
+
+	destRect := &sdl.Rect{
+		W: s.width, H: s.height,
+	}
+
+	if err := s.renderer.SetRenderTarget(sdlTargetSurface.texture); err != nil {
+		return err
+	}
+
+	if err := s.renderer.Copy(s.texture, nil, destRect); err != nil {
+		return err
+	}
+
+	if err := s.renderer.SetRenderTarget(nil); err != nil {
+		return err
+	}
+
+	return nil
+}