mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-28 04:38:55 +01:00
86 lines
2.3 KiB
Go
86 lines
2.3 KiB
Go
package shader
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// #cgo LDFLAGS: -framework OpenGL
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//
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// #include <OpenGL/gl.h>
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// #include <stdlib.h>
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import "C"
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import (
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"github.com/hajimehoshi/go-ebiten/graphics"
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"github.com/hajimehoshi/go-ebiten/graphics/matrix"
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"github.com/hajimehoshi/go-ebiten/graphics/opengl/texture"
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"sync"
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"unsafe"
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)
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var once sync.Once
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func DrawTexture(native texture.Native, projectionMatrix [16]float32, quads []graphics.TextureQuad, geometryMatrix matrix.Geometry, colorMatrix matrix.Color) {
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once.Do(func() {
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initialize()
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})
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if len(quads) == 0 {
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return
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}
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shaderProgram := use(projectionMatrix, geometryMatrix, colorMatrix)
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defer C.glUseProgram(0)
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C.glBindTexture(C.GL_TEXTURE_2D, C.GLuint(native))
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defer C.glBindTexture(C.GL_TEXTURE_2D, 0)
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vertexAttrLocation := getAttributeLocation(shaderProgram, "vertex")
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texCoordAttrLocation := getAttributeLocation(shaderProgram, "tex_coord")
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C.glEnableClientState(C.GL_VERTEX_ARRAY)
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C.glEnableClientState(C.GL_TEXTURE_COORD_ARRAY)
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C.glEnableVertexAttribArray(C.GLuint(vertexAttrLocation))
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C.glEnableVertexAttribArray(C.GLuint(texCoordAttrLocation))
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defer func() {
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C.glDisableVertexAttribArray(C.GLuint(texCoordAttrLocation))
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C.glDisableVertexAttribArray(C.GLuint(vertexAttrLocation))
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C.glDisableClientState(C.GL_TEXTURE_COORD_ARRAY)
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C.glDisableClientState(C.GL_VERTEX_ARRAY)
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}()
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vertices := []float32{}
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texCoords := []float32{}
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indicies := []uint32{}
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// TODO: Check len(parts) and GL_MAX_ELEMENTS_INDICES
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for i, quad := range quads {
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x1 := quad.VertexX1
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x2 := quad.VertexX2
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y1 := quad.VertexY1
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y2 := quad.VertexY2
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vertices = append(vertices,
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x1, y1,
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x2, y1,
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x1, y2,
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x2, y2,
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)
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u1 := quad.TextureCoordU1
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u2 := quad.TextureCoordU2
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v1 := quad.TextureCoordV1
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v2 := quad.TextureCoordV2
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texCoords = append(texCoords,
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u1, v1,
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u2, v1,
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u1, v2,
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u2, v2,
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)
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base := uint32(i * 4)
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indicies = append(indicies,
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base, base+1, base+2,
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base+1, base+2, base+3,
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)
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}
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C.glVertexAttribPointer(C.GLuint(vertexAttrLocation), 2,
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C.GL_FLOAT, C.GL_FALSE,
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0, unsafe.Pointer(&vertices[0]))
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C.glVertexAttribPointer(C.GLuint(texCoordAttrLocation), 2,
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C.GL_FLOAT, C.GL_FALSE,
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0, unsafe.Pointer(&texCoords[0]))
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C.glDrawElements(C.GL_TRIANGLES, C.GLsizei(len(indicies)),
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C.GL_UNSIGNED_INT, unsafe.Pointer(&indicies[0]))
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}
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