The following is the contents of the standard input, which creates a red bullet on a white background. If the bc.ini file is corrupted you can delete the corrupt file and create this standard file by running the program.
You can activate any line in the following input to go to the section in this manual that explains what that line stands for.
The image section deals with the appearance of the scene set up in the other sections.
This is the name of the file the image is written to. Any valid DOS name will do. The program will not warn if a file is about to be overwritten.
The type of the image is either tga for a True Color Truevision TGA® format or anything else for a headerless 24-bit RGB raw pixel format file. The quality of both image types is the same. TGA can be read directly into some graphics programs, while for reading a raw format the images' width, height, color-depth, ordering and orientation have to be given by the user. The way in which the raw format is used is as follows:
| Header Size: | 0 bytes |
|---|---|
| Channels: | Three Channel RGB |
| Grouping: | Interleaved RGB |
| Ordering: | RGB |
| Orientation: | Bottom down / not flipped |
Due to internal programming limitations the RAW type is created a bit faster because it uses a 600 pixel cache, while the TGA cache is limited to 6 pixels.
The program creates square images with a width and height in pixels of the value of size. For bullet-images a size of around 15 will suffice, but images with a larger size can be created, just limited by disk-space and time you want to spend computing. A size of 50 is a good size to use for preview images, especially if your graphics program can zoom in on it.
When opening a headerless raw pixel format file you will have to specify the width and height of the image. If you don't remember the size of a raw bullet image you can calculate it by taking it's filesize on disk in bytes, devide that by 3 to get the number of pixels in the image and the square root of that is the width and height of the image in pixels.
The zoom factor determines how much space is created around the bullet. A factor of 1 will just show the bullet in the image and leave not much room for a shadow. Depending on the length of the shadow being cast choose a larger zoom factor. At sunset even a short man casts a long shadow...
The autozoom function can be used by specifying a zoom factor of zero. The program will then calculate how long the shadow will be and use an appropriate zoom factor. If the input makes the calculated zoomfactor too large (>700) it will set it to 1.
The view factor sets the distance of the eyepoint from which the scene is being viewed. Usually a large value will do and smaller values create a fish-eye effect.
| The sample image with a view value of 5 creates a fish-eye effect with a larger bullet and a relatively small shadow. | small | large | The sample image with a view value of 500 has little distortion. Notice the shadow is in both images concealed in the image because the zoom factor is unchanged. |
The number of samples that will be taken to determine the color value of a pixel, a square number. If not square the root will be rounded. Oversampling reduces aliasing and generates smoother pictures, but at the cost of increasing calculation time. Especially in small images a high samples value creates nicer images.
It is best to create small preview images without oversampling (factor 1) in little time and then, when the image looks like you want it to be, increase the size and oversampling when creating the ultimate picture.
4x enlarged sample image without oversampling (factor 1). |
4x enlarged sample image with 4-times oversampling. |
4x enlarged sample image with 9-times oversampling. |
The color intensities consist of the three values for a red, green and blue component. Normal values are between 0 and 1, but values beyond that can be used to force specific results.
For converting from other color formats see Converting Color values.
The overall contributions to the light intensities shouldn't be much beyond the 0 to 1 range to avoid under- or overexposed images. Experiment with different values for lighting as well as material to examine the large variety of effects.
The color intensities of the ambient light. Multiplied by the ambient color factors this parameter influences the color of objects in the shadow. No ambient light causes black shadows.
The color intensities of the directed light. Multiplied by the diffuse and specular factors this parameter influences the color of objects hit by the directed light.
This is the direction the directed light is shining in. Positive X-axis is directed towards the right, positive Y-axis down and Z-axis directed inwards the screen. With all three values positive the shadow is cast in the bottom-right corner. A light direction pointing out of the screen is only useful with a background radius much smaller than 1 because only then the bullet isn't shadowed over by the background bullet.
Here the material parameters for the bullet and the background are defined.
This determines the maximum part of the color intensities of the ambient light that can be reflected by an object. This is the color of an object in white ambient light.
This determines the maximum part of the color intensities of the directed light that can be reflected by an object due to reflectiveness of the object for the different color intensities. Together with the color of the directed light this determines the color of the object when hit by directed light.
This determines the color of the highlight together with the directed light color. It works the same as the diffuse factor but not orientated around the light direction but light direction when mirrored in the surface of the sphere.
This indicates the spread of the highlight. A high factor gives a more glossy effect, with a concentrated highlight. Usually all three factors are the same, but for special effects different highlight spreading can be used for the three color components.
In this section the rest of the parameters for the appearance of the bullet are specified.
The elevation of the bullet is the distance the bullet is placed 'above' the background. This value can be anything, but with the same lighting the zoom factor will have to be increased to get the shadow in the image. At values less that -1 the bullet has disappeared in the background. Values between -1 and 1 make it partially enclosed in the background, with 0 making the bullet a hemisphere. Assumed here is that the background radius is very large.
The texture of the bullet is a 24 bit uncompressed TGA format file which will be mapped on the visible side of the bullet. Use a non-existing name to use just the material colors of the bullet.
The repetition is how many times the mapped image has to be repeated in horizontal and vertical space. The first value is the amount of horizontal repetitions, the second is for vertical. Values less than 1 zoom in on the mapped image. Standard the mapped image is centered, so an even repetition value has one repeated image split and distributed on the edges of the sphere.
With the shift values you can shift the mapped image in horizontal and vertical positions. The value is the part of the image it has to be shifted over, so the integer part has no effect.
The mapADS triple is used to merge the mapped image with the material colors of the bullet. A value of 1 means that just the mapped image is used to determine bulletKa, bulletKd and bulletKs, while 0 means the mapped image is ignored. Values between these borders merge the bullet material values with the mapped image.
The mapping is an integer which indicates the type of mapping that will be used:
| Mapping | Description | Example |
|---|---|---|
| 1 | Fish-eye: Straight lines in the picture bend towards the top, bottom, left and right sides of the sphere. | |
| 2 | Mercator: Lines only bend towards the top and bottom of the sphere, like the meridians get together at the north and south pole. The parallels stay, of course, parallel. | |
| 3 | Flat: All parallel lines stay parallel, but get closer together near the edge. |
In this section the rest of the parameters for the appearance of the background are specified.
The background radius is the radius of the sphere used as a background. Usually this is a large value to make the background appear as a plane. The bullet radius is 1, so smaller values for the background will make the background disappear. A radius of 0 indicates no background, so no shadow can be cast. Other values can be used for special effects.
The infinity values are the color values for the background behind the two spheres, i.e. the color of the space behind them.
The flat value is either 0 or 1. A value of 0 means that the background is rendered as a sphere, in the same way as the bullet. This makes it difficult to control the background color. If you want to specify the background color you can set it in the infinity parameter and set flat to 1. In this way the background is treated as flat and is set to the infinity value. The difference with setting the background radius to 0 is that the flat method still casts a shadow on the background. For a semi-realistic background color the material colors for the background have to be about the same as the infinity color. Otherwise the shadow will have a color that doesn't fit the background color it is cast upon.