func (cube *Cube) Draw() {
/* Bind cube vertices. Note that this is in attribute index 0 */
gl.BindBuffer(gl.ARRAY_BUFFER, cube.bufferObject)
gl.EnableVertexAttribArray(0)
gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 0, nil)
/* Bind cube colours. Note that this is in attribute index 1 */
gl.BindBuffer(gl.ARRAY_BUFFER, cube.coloursObject)
gl.EnableVertexAttribArray(1)
gl.VertexAttribPointer(1, 4, gl.FLOAT, false, 0, nil)
/* Bind cube normals. Note that this is in attribute index 2 */
gl.EnableVertexAttribArray(2)
gl.BindBuffer(gl.ARRAY_BUFFER, cube.normalsObject)
gl.VertexAttribPointer(2, 3, gl.FLOAT, false, 0, nil)
// Enable this line to show model in wireframe
if cube.DrawMode == DRAW_LINES {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
} else {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
}
/* Draw our cube*/
if cube.DrawMode == DRAW_POINTS {
gl.DrawArrays(gl.POINTS, 0, int32(32))
} else {
gl.DrawArrays(gl.TRIANGLES, 0, 36)
}
}
// Draws the sphere form the previously defined vertex and index buffers
func (sphere *Sphere) Draw() {
// Adds the Sphere Model to the Active Shader
sphere.ShaderManager.SetUniformMatrix4fv(sphere.ShaderManager.ActiveShader, "model", 1, false, &sphere.Model[0])
/* Draw the vertices as GL_POINTS */
gl.BindBuffer(gl.ARRAY_BUFFER, sphere.sphereBufferObject)
gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 0, nil)
gl.EnableVertexAttribArray(0)
/* Bind the sphere colours */
gl.BindBuffer(gl.ARRAY_BUFFER, sphere.sphereColours)
gl.VertexAttribPointer(1, 4, gl.FLOAT, false, 0, nil)
gl.EnableVertexAttribArray(1)
/* Bind the sphere normals */
gl.BindBuffer(gl.ARRAY_BUFFER, sphere.sphereNormals)
gl.VertexAttribPointer(2, 3, gl.FLOAT, false, 0, nil)
gl.EnableVertexAttribArray(2)
gl.PointSize(3.0)
// Enable this line to show model in wireframe
if sphere.DrawMode == DRAW_LINES {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
} else {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
}
if sphere.DrawMode == DRAW_POINTS {
gl.DrawArrays(gl.POINTS, 0, int32(sphere.numSphereVertices))
} else {
/* Bind the indexed vertex buffer */
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, sphere.elementBuffer)
/* Draw the north pole regions as a triangle */
gl.DrawElements(gl.TRIANGLE_FAN, int32(sphere.numLongs+2), gl.UNSIGNED_INT, nil)
/* Calculate offsets into the indexed array. Note that we multiply offsets by 4
because it is a memory offset the indices are type GLuint which is 4-bytes */
var lat_offset_jump int = int((sphere.numLongs * 2) + 2)
var lat_offset_start int = int(sphere.numLongs + 2)
var lat_offset_current int = lat_offset_start * 4
var i uint32
/* Draw the triangle strips of latitudes */
for i = 0; i < sphere.numLats-2; i++ {
gl.DrawElements(gl.TRIANGLE_STRIP, int32(sphere.numLongs*2+2), gl.UNSIGNED_INT, gl.PtrOffset(lat_offset_current))
lat_offset_current += (lat_offset_jump * 4)
}
/* Draw the south pole as a triangle fan */
gl.DrawElements(gl.TRIANGLE_FAN, int32(sphere.numLongs+2), gl.UNSIGNED_INT, gl.PtrOffset(lat_offset_current))
}
}
// Draws the cog form the previously defined vertex and index buffers
func (cog *Cog) Draw() {
// Adds the Sphere Model to the Active Shader
cog.ShaderManager.SetUniformMatrix4fv(cog.ShaderManager.ActiveShader, "model", 1, false, &cog.Model[0])
/* Draw the vertices as GL_POINTS */
gl.BindBuffer(gl.ARRAY_BUFFER, cog.cogBufferObject)
gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 0, nil)
gl.EnableVertexAttribArray(0)
/* Bind the sphere colours */
gl.BindBuffer(gl.ARRAY_BUFFER, cog.cogColours)
gl.VertexAttribPointer(1, 4, gl.FLOAT, false, 0, nil)
gl.EnableVertexAttribArray(1)
/* Bind the sphere normals */
gl.BindBuffer(gl.ARRAY_BUFFER, cog.cogNormals)
gl.VertexAttribPointer(2, 3, gl.FLOAT, false, 0, nil)
gl.EnableVertexAttribArray(2)
gl.PointSize(3.0)
// Enable this line to show model in wireframe
if cog.DrawMode == DRAW_LINES {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
} else {
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
}
if cog.DrawMode == DRAW_POINTS {
gl.DrawArrays(gl.POINTS, 0, int32(cog.numCogVertices))
} else {
// Bind the indexed vertex buffer
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, cog.elementBuffer)
// Draw the north pole regions as a triangle
gl.DrawElements(gl.TRIANGLE_FAN, int32(cog.VerticesPerDisk+2), gl.UNSIGNED_INT, nil)
// Calculate offsets into the indexed array. Note that we multiply offsets by 4
// because it is a memory offset the indices are type GLuint which is 4-bytes
var lat_offset_jump int = int((cog.VerticesPerDisk * 2) + 2)
var lat_offset_start int = int(cog.VerticesPerDisk + 2)
var lat_offset_current int = lat_offset_start * 4
// Draw the triangle strips of Sides
gl.DrawElements(gl.TRIANGLE_STRIP, int32(cog.VerticesPerDisk*2+2), gl.UNSIGNED_INT, gl.PtrOffset(lat_offset_current))
lat_offset_current += (lat_offset_jump * 4)
// Draw the south pole as a triangle fan
gl.DrawElements(gl.TRIANGLE_FAN, int32(cog.VerticesPerDisk+2), gl.UNSIGNED_INT, gl.PtrOffset(lat_offset_current))
}
}
func (objectLoader *WavefrontObject) DrawObject(shaderProgram uint32) {
for _, object := range objectLoader.Objects {
// Reads the uniform Locations
modelUniform := gl.GetUniformLocation(shaderProgram, gl.Str("model\x00"))
ambientUniform := gl.GetUniformLocation(shaderProgram, gl.Str("ambient\x00"))
diffuseUniform := gl.GetUniformLocation(shaderProgram, gl.Str("diffuse\x00"))
specularUniform := gl.GetUniformLocation(shaderProgram, gl.Str("specular\x00"))
emissiveUniform := gl.GetUniformLocation(shaderProgram, gl.Str("emissive\x00"))
// Send our uniforms variables to the currently bound shader
if object.Material != nil {
gl.Uniform4f(ambientUniform, object.Material.KaR, object.Material.KaG, object.Material.KaB, object.Material.Tr) // Ambient colour.
gl.Uniform4f(diffuseUniform, object.Material.KdR, object.Material.KdG, object.Material.KdB, object.Material.Tr) // Diffuse colour.
gl.Uniform4f(specularUniform, object.Material.KsR, object.Material.KsG, object.Material.KsB, object.Material.Tr) // Specular colour.
gl.Uniform4f(emissiveUniform, object.Material.KeR, object.Material.KeG, object.Material.KeB, object.Material.Tr) // Emissive colour.
if object.Material.Texture != 0 {
textureUniform := gl.GetUniformLocation(shaderProgram, gl.Str("DiffuseTextureSampler\x00"))
gl.Uniform1i(textureUniform, 0)
normalTextureUniform := gl.GetUniformLocation(shaderProgram, gl.Str("NormalTextureSampler\x00"))
gl.Uniform1i(normalTextureUniform, 1)
specularTextureUniform := gl.GetUniformLocation(shaderProgram, gl.Str("SpecularTextureSampler\x00"))
gl.Uniform1i(specularTextureUniform, 2)
gl.ActiveTexture(gl.TEXTURE0)
gl.BindTexture(gl.TEXTURE_2D, object.Material.Texture)
gl.ActiveTexture(gl.TEXTURE1)
gl.BindTexture(gl.TEXTURE_2D, object.Material.NormalMap)
gl.ActiveTexture(gl.TEXTURE2)
gl.BindTexture(gl.TEXTURE_2D, object.Material.SpecularMap)
}
if object.Material.Tr < 1.0 {
// Enables Transparencies
gl.Enable(gl.BLEND)
// gl.BlendFunc(gl.SRC_COLOR, gl.ONE)
// gl.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA)
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
}
}
// Geometry
var size int32 // Used to get the byte size of the element (vertex index) array
gl.UniformMatrix4fv(modelUniform, 1, false, &object.Model[0])
// Get the vertices uniform position
verticesUniform := uint32(gl.GetAttribLocation(shaderProgram, gl.Str("position\x00")))
normalsUniform := uint32(gl.GetAttribLocation(shaderProgram, gl.Str("normal\x00")))
textureCoordinatesUniform := uint32(gl.GetAttribLocation(shaderProgram, gl.Str("texcoord\x00")))
// Describe our vertices array to OpenGL (it can't guess its format automatically)
gl.BindBuffer(gl.ARRAY_BUFFER, object.VertexBufferObjectVertices)
gl.VertexAttribPointer(
verticesUniform, // attribute index
3, // number of elements per vertex, here (x,y,z)
gl.FLOAT, // the type of each element
false, // take our values as-is
0, // no extra data between each position
nil, // offset of first element
)
gl.EnableVertexAttribArray(normalsUniform)
gl.BindBuffer(gl.ARRAY_BUFFER, object.VertexBufferObjectNormals)
gl.VertexAttribPointer(
normalsUniform, // attribute
3, // number of elements per vertex, here (x,y,z)
gl.FLOAT, // the type of each element
false, // take our values as-is
0, // no extra data between each position
nil, // offset of first element
)
gl.EnableVertexAttribArray(textureCoordinatesUniform)
gl.BindBuffer(gl.ARRAY_BUFFER, object.VertexBufferObjectTextureCoords)
gl.VertexAttribPointer(
textureCoordinatesUniform, // attribute
2, // number of elements per vertex, here (u,v)
gl.FLOAT, // the type of each element
false, // take our values as-is
0, // no extra data between each position
nil, // offset of first element
)
size = int32(len(object.Vertex))
gl.PointSize(3.0)
// Enable this line to show model in wireframe
switch objectLoader.DrawMode {
case 1:
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
default:
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
}
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, object.VertexBufferObjectFaces)
gl.GetBufferParameteriv(gl.ELEMENT_ARRAY_BUFFER, gl.BUFFER_SIZE, &size)
gl.DrawElements(gl.TRIANGLES, int32(len(object.Faces)), gl.UNSIGNED_SHORT, nil)
// gl.DrawElements(gl.POINTS, int32(len(object.Faces)), gl.UNSIGNED_SHORT, nil)
// Disables transparencies
gl.Disable(gl.BLEND)
}
}
/* Enable vertex attributes and draw object
Could improve efficiency by moving the vertex attribute pointer functions to the
create object but this method is more general
This code is almost untouched fomr the tutorial code except that I changed the
number of elements per vertex from 4 to 3*/
func (terrain *Terrain) DrawObject(shaderProgram uint32) {
toneUniform := gl.GetAttribLocation(shaderProgram, gl.Str("tone\x00"))
gl.Uniform4f(toneUniform, terrain.ColorTone.X(), terrain.ColorTone.Y(), terrain.ColorTone.Z(), terrain.ColorTone.W())
// gl.Uniform4f(toneUniform, 0.0, 1.0, 0.5, 1.0)
// gl.Uniform4fv(toneUniform, 1, &terrain.ColorTone[0])
// Reads the uniform Locations
modelUniform := gl.GetUniformLocation(shaderProgram, gl.Str("model\x00"))
// Send our uniforms variables to the currently bound shader
gl.UniformMatrix4fv(modelUniform, 1, false, &terrain.Model[0])
// Get the vertices uniform position
verticesUniform := uint32(gl.GetAttribLocation(shaderProgram, gl.Str("position\x00")))
normalsUniform := uint32(gl.GetAttribLocation(shaderProgram, gl.Str("normal\x00")))
colorsUniform := uint32(gl.GetAttribLocation(shaderProgram, gl.Str("colour\x00")))
// Describe our vertices array to OpenGL (it can't guess its format automatically)
gl.EnableVertexAttribArray(verticesUniform)
gl.BindBuffer(gl.ARRAY_BUFFER, terrain.VBOVertices)
gl.VertexAttribPointer(
verticesUniform, // attribute index
3, // number of elements per vertex, here (x,y,z)
gl.FLOAT, // the type of each element
false, // take our values as-is
0, // no extra data between each position
nil, // offset of first element
)
gl.EnableVertexAttribArray(normalsUniform)
gl.BindBuffer(gl.ARRAY_BUFFER, terrain.VBONormals)
gl.VertexAttribPointer(
normalsUniform, // attribute
3, // number of elements per vertex, here (x,y,z)
gl.FLOAT, // the type of each element
false, // take our values as-is
0, // no extra data between each position
nil, // offset of first element
)
gl.EnableVertexAttribArray(colorsUniform)
gl.BindBuffer(gl.ARRAY_BUFFER, terrain.VBOColors)
gl.VertexAttribPointer(
colorsUniform, // attribute
3, // number of elements per vertex, here (x,y,z)
gl.FLOAT, // the type of each element
false, // take our values as-is
0, // no extra data between each position
nil, // offset of first element
)
size := int32(len(terrain.Indices))
gl.PointSize(3.0)
gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, terrain.VBOIndices)
gl.GetBufferParameteriv(gl.ELEMENT_ARRAY_BUFFER, gl.BUFFER_SIZE, &size)
// Enable this line to show model in wireframe
switch terrain.DrawMode {
case 1:
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
case 2:
gl.DrawArrays(gl.POINTS, 0, int32(len(terrain.Vertices)))
// gl.DrawElements(gl.POINTS, int32(len(terrain.Indices)), gl.UNSIGNED_SHORT, nil)
return
default:
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
}
var location int = 0
/* Draw the triangle strips */
for i := uint32(0); i < terrain.XSize-1; i++ {
location = SizeOfUint16 * int(i*terrain.ZSize*2)
gl.DrawElements(gl.TRIANGLE_STRIP, int32(terrain.ZSize*2), gl.UNSIGNED_SHORT, gl.PtrOffset(location))
}
// gl.DrawElements(
// gl.TRIANGLE_STRIP,
// len(terrain.Indices),
// gl.UNSIGNED_SHORT,
// nil,
// )
}